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1
Wells-Berlin, Alicia M., Harold H. Prince e Todd W. Arnold. "Incubation Length of Dabbling Ducks". Condor 107, n. 4 (1 novembre 2005): 926–29. http://dx.doi.org/10.1093/condor/107.4.926.
Testo completoAbstract (sommario):
AbstractWe collected unincubated eggs from wild Mallard (Anas platyrhynchos), Gadwall (A. strepera), Blue-winged Teal (A. discors), and Northern Shoveler (A. clypeata) nests and artificially incubated them at 37.5°C. Average incubation lengths of Mallard, Gadwall, and Northern Shoveler eggs did not differ from their wild-nesting counterparts, but artificially incubated Blue-winged Teal eggs required an additional 1.7 days to hatch, suggesting that wild-nesting teal incubated more effectively. A small sample of Mallard, Gadwall, and Northern Shoveler eggs artificially incubated at 38.3°C hatched 1 day sooner, indicating that incubation temperature affected incubation length. Mean incubation length of Blue-winged Teal declined by 1 day for each 11-day delay in nesting, but we found no such seasonal decline among Mallards, Gadwalls, or Northern Shovelers. There is no obvious explanation for the seasonal reduction in incubation length for Blue-winged Teal eggs incubated in a constant environment, and the phenomenon deserves further study.
2
Titman, Rodger, Elise Titman e Shawn Craik. "Timing of pair formation and male acquisition of alternate plumage by three wintering dabbling ducks". Canadian Field-Naturalist 135, n. 1 (23 giugno 2021): 39–46. http://dx.doi.org/10.22621/cfn.v135i1.2547.
Testo completoAbstract (sommario):
Pair formation in ducks is thought to be influenced by the acquisition of breeding plumage, the occurrence of courtship display, or both. We examined the frequency of pair formation in Mallard (Anas platyrhynchos), Green-winged Teal (Anas crecca carolinensis), and Northern Shoveler (Spatula clypeata) in the central valley of California in relation to the frequencies of male attainment of breeding plumage and courtship display. Predictions related to two hypotheses are: (1) the timing of pair formation is directly related to the attainment of breeding (definitive alternate) plumage by males, and (2) frequencies of courtship display are highest during pair formation. Most female Mallard were paired by the end of October, with >80% in pairs by early December. Of Northern Shoveler, 90% were paired by early January and 90% of female Green-winged Teal were paired by early February. The highest rates of courtship display by Mallard were observed during October through November, by Northern Shoveler in November, and by Green-winged Teal in November through January. Courtship display was, therefore, relatively frequent at the same time as pair formation for all three species. Northern Shoveler spent less time in courtship display than the other two species. Most (90%) male Mallard had acquired alternate plumage by mid-November, Northern Shoveler by early February, and Green-winged Teal by mid-December. Thus, timing of pair formation coincided with timing of attainment of breeding plumage in Mallard and Green-winged Teal but not Northern Shoveler.
3
Slimane, Ayeb, Elafri Ali e Salah Telailia. "Northern Shoveler Spatula clypeata: a possible first breeding record for Algeria". Biodiversity Observations 13 (24 febbraio 2023): 142–45. http://dx.doi.org/10.15641/bo.1210.
Testo completoAbstract (sommario):
Breeding events of a waterbird species outside of their normal breeding grounds could be important to address how population changes on wintering areas are impacted by changes elsewhere in the birds’ annual cycle. In this note we confirm the first breeding record of Northern Shoveler Spatula clypeata in Algeria. The breeding site was a saline lake, Sebkhet El-mahmel, located 180 km from the Mediterranean Sea and subject to a semi-arid climate. The area was visited on 16 June 2019 and the species was confirmed as a pair of Northern Shoveler accompanied by eight juveniles. The Northern Shoveler is an unmistakable waterbird species in the northern hemisphere due to its distinctive bill. The female and her juveniles looked healthy and they spent almost the entire daytime foraging and swimming.
4
DuBowy, Paul J. "Feeding ecology and behavior of postbreeding male Blue-winged Teal and Northern Shovelers". Canadian Journal of Zoology 63, n. 6 (1 giugno 1985): 1292–97. http://dx.doi.org/10.1139/z85-194.
Testo completoAbstract (sommario):
This study examined foraging strategies in male Northern Shovelers (Anas clypeata) and Blue-winged Teal (Anas discors). Differences in time–activity budgets and esophageal contents between the two species indicated major differences in the degree of foraging specialization. Preflightless male Northern Shovelers spent 84.2% of time foraging, with dabbling in the water column as the principal foraging mode (83.4%), while postflightless male shovelers spent 81.6% of time foraging (78.7% dabbling). Preflightless male Blue-winged Teal spent 68.6% of time foraging, with dabbling in mud (32.5%) and picking in vegetation (29.4%) as the two principal modes, whereas postflightless male bluewings spent 85.9% of time foraging (dabbling in mud 40.6%, and picking 34.2%). Most male Northern Shoveler food items were cladocerans (85.5%) or chironomid pupae (12.9%); this was related to the specialized foraging method employed by shovelers. Male Blue-winged Teal food items were principally gastropods (44.3%), culicids (29.2%), seeds and vegetation (15.5%), and chironomids (5.6%), which corresponded to the plastic feeding behaviors of bluewings. Examination of esophageal items revealed that male Northern Shovelers did little feeding during the summer flightless period, while male Blue-winged Teal fed throughout the period.
5
Krapu, Gary L., Ronald E. Reynolds, Glen A. Sargeant e Randy W. Renner. "Patterns of Variation in Clutch Sizes in a Guild of Temperate-Nesting Dabbling Ducks". Auk 121, n. 3 (1 luglio 2004): 695–706. http://dx.doi.org/10.1093/auk/121.3.695.
Testo completoAbstract (sommario):
Abstract We investigated patterns and causes of variation in clutch sizes in a guild of five species of temperate-nesting dabbling ducks (Mallard [Anas platyrhynchos], Northern Pintail [“pintail,” A. acuta], Gadwall [A. strepera], Blue-winged Teal [“teal,” A. discors], and Northern Shoveler [“shoveler,” A. clypeata]) during 1993-1995 in the Prairie Pothole Region of midcontinental North America. Clutch sizes (mean ± SE) were largest for teal (10.80 ± 0.03), followed in descending order by those of shoveler (10.31 ± 0.05), Gadwall (9.92 ± 0.04), Mallard (8.91 ± 0.04), and pintail (7.66 ± 0.06). In Mallard, pintail, and shoveler, predicted clutch sizes at onset of nesting exhibited minimal variation. Clutch sizes of Gadwall and teal displayed statistically significant variation among years at onset of nesting; pintail clutch sizes showed significant variation late in the nesting season. Clutch sizes declined seasonally in all species. Declines in clutch sizes of teal and shoveler were approximately linear; whereas clutch sizes of Mallard, pintail, and Gadwall usually declined at progressively decreasing rates. Linear declines in teal and shoveler clutches suggest that those species experienced greater difficulty securing lipids for egg production late in the nesting season than did Mallard, pintail, and Gadwall. That disparity may result because egg-laying female teal and shoveler feed almost exclusively on animal foods, which are primarily protein; whereas female Mallard, pintail, and Gadwall consume more carbohydrate-rich plant foods. Our findings, when examined in context with existing information, suggest that interspecific variation in clutch sizes results from innate differences in several traits—including body size, diet, timing of lipid acquisition, and nesting—all of which can affect the amount of lipid available for egg production. Temperate-nesting dabbling ducks have evolved traits that facilitate laying of large clutches early in the nesting season, because risk of mortality is lower among early-hatched young. Annual differences in clutch sizes of all five species were not significant when effects of annual variation in nest-initiation dates were accounted for, reflecting the key role of environmental influences on intraspecific variation in clutch sizes among years.
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Krapu, Gary L. "Temporal Flexibility of Reproduction in Temperate-Breeding Dabbling Ducks". Auk 117, n. 3 (1 luglio 2000): 640–50. http://dx.doi.org/10.1093/auk/117.3.640.
Testo completoAbstract (sommario):
AbstractI compared nesting intervals during three consecutive years in five species of temperate-nesting dabbling ducks (Mallard [Anas platyrhynchos], Northern Pintail [Anas acuta], Northern Shoveler [Anas clypeata], Blue-winged Teal [Anas discors], Gadwall [Anas strepera]) and assessed whether differences existed in timing of refractoriness. Most nesting by females of all five species ended by the summer solstice. Nesting ended earliest for Northern Shovelers and Northern Pintails and latest for Gadwalls. Some Mallards, Blue-winged Teal, and Gadwalls continued to nest into mid- and late summer, whereas Northern Shovelers and Northern Pintails did not. Mallards, Blue-winged Teal, and Gadwalls accounted for 99% (81 of 82) of flightless broods resulting from nests initiated during mid- or late summer in North Dakota and 98% (58 of 59) of flightless juveniles shot on or after 1 October by a random sample of duck hunters from across the United States. Early cessation of breeding by Northern Shovelers may have evolved in response to the species' limited flexibility in diet. Photorefractory mechanisms that limit most breeding to spring presumably evolved in response to severe constraints on reproductive success when nesting continued through summer (e.g. mortality of late-hatched young and molting females due to low temperatures). Interspecific differences in photosensitivity may account for variation in timing of cessation of nesting in late spring, but controlled experiments are needed to assess the possible role of non-photic influences. My results suggest that the refractory mechanisms controlling length of the breeding season in temperate-nesting dabbling ducks are more varied and complex than previously thought, with non-photic influences (e.g. water conditions, food availability, food quality) having a larger role than indicated by earlier research.
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El Rahman, Mokhless Ahmed Mohamed Abd, Ahmed Hamed Khalifa e Ahmed Shabaan Badri Ashour. "Carcass Characteristics, Physicochemical Properties and Nutritional Composition of Meat from two Wild Birds: Northern Pintail (Anas acuta) and Northern Shoveler (Spatula clypeata)". International Journal of Current Microbiology and Applied Sciences 11, n. 8 (10 agosto 2022): 130–46. http://dx.doi.org/10.20546/ijcmas.2022.1108.013.
Testo completoAbstract (sommario):
The objective of this study was to evaluate the characteristics of the carcass, physicochemical properties as well as nutritional composition in breast and leg meat (with skin) of two different genotypes of wild birds namely: pintail (Anas acuta) and shoveler (Spatula clypeata) with regard to sex effect. The study involved forty-eight birds, 24 pintail and 24 shovelers (1:1 sex ratio) harvested during the hunting season (in September and November 2020) in lake Nasser from the Gerf-Hussein region, south Aswan Government. After the slaughter and dissection. PH, WHC and color coordinates of the breast and leg muscles were specified after 24 h of slaughter. After the dissection, breast and leg meats minced with their skin were sampled to determine cross composition, some minerals, amino acids profiles. The studied birds showed significant differences in body weight (BW), carcass weight, dressing percentage and percentages of neck and gizzard. Genotype affected the redness (a*), yellowness (b*), moisture, fat, ash and energy value of breast muscles, and also pH24, lightness (L*), redness (a*), moisture, fat, ash and energy value of leg muscles. Regardless of genotype, males showed higher body weight, carcass weight, as well as breast and leg cuts weight compared to females. The shovelers had a higher content of K, Mg, Ca, Fe and Co in breast and leg muscles compared to the pintail. While Pb and Cd exceeded maximum admissible levels which are recommended by European common regulation. Cd was detected only in breast and leg muscles from pintail. The essential amino acid content ranged from 39.73-44.45 g/100 g protein in pintails against 41.46-44.94 g/100 g protein in shovelers.
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Loos, Elizabeth R., e Frank C. Rohwer. "Laying-Stage Nest Attendance and Onset of Incubation in Prairie Nesting Ducks". Auk 121, n. 2 (1 aprile 2004): 587–99. http://dx.doi.org/10.1093/auk/121.2.587.
Testo completoAbstract (sommario):
Abstract We used microprocessor data loggers to document patterns of nest attendance during the laying stage and to quantify temperatures of dummy eggs during laying for Mallard (Anas platyrhynchos), Blue-winged Teal (A. discors), Northern Shoveler (A. clypeata), Northern Pintail (A. acuta), Gadwall (A. strepera), Green-winged Teal (A. crecca), American Wigeon (A. americana), and Lesser Scaup (Aythya affinis) nesting in southern Manitoba in 1994 and in northeastern North Dakota in 1995–1997 and 2000–2002. Females of all species increased the time they spent on the nest as laying progressed, but species differed in their pattern of increased attendance. Female Blue-winged Teal and Northern Shoveler that laid smaller clutches increased the time they spent on the nest more rapidly than conspecifics that laid larger clutches, but large- and small-clutch conspecifics had similar attendance at the end of the laying period. Attendance during laying was not influenced by low ambient temperature, precipitation, or nest initiation date. For all species combined, maximum egg temperatures increased as laying progressed. Eggs were heated to temperatures sufficient for embryonic development as early as the day that the second egg was laid. Our findings contradict the prevailing paradigm that incubation in waterfowl begins after clutch completion and raise questions about how hatching synchrony is achieved. We relate our findings to two hypotheses (nutrient limitation and viability–predation) that have been proposed to explain the limits to clutch size in ducks.
9
MATUBARA, Takeshi. "Esophageal and Gizzard Contents of Northern Shoveler(Anas clypeata) in Lake Teganuma." Japanese Journal of Limnology (Rikusuigaku Zasshi) 53, n. 4 (1992): 373–77. http://dx.doi.org/10.3739/rikusui.53.373.
Testo completo
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Heitmeyer, Mickey E. "Influences of age, body condition, and structural size on mate selection by dabbling ducks". Canadian Journal of Zoology 73, n. 12 (1 dicembre 1995): 2251–58. http://dx.doi.org/10.1139/z95-267.
Testo completoAbstract (sommario):
Both members of pairs of mallards (Anas platyrhynchos), northern pintails (Anas acuta), northern shovelers (Anas clypeata), and American wigeon (Anas americana) were collected early in the pairing periods in fall and during spring migration (several months after most birds were paired) to provide insights into whether (i) assortative mating occurs; (ii) body condition changes synchronously among pair members; and (iii) characteristics of selected individuals ultimately confer advantages in survival and recruitment. Both members in 19 of 21 mallard, 16 of 16 pintail, 14 of 14 shoveler, and 14 of 15 wigeon pairs were adults. The predominance of adults in pairs in fall indicates that adults pair earlier than juveniles and suggests at least some assortative mating in relation to age. Generally, body and nutrient reserve masses of males and females within a pair were correlated for all species in both fall and spring, suggesting that individuals tend to form pairs with others of relatively similar body condition, and also that once paired, the body condition of the two members tends to change at the same time. In contrast to body condition, measures of structural size of pair members were not correlated. Field data suggest that older and heavier ducks have greater survival and reproductive potential than young, lighter ducks; consequently, selection of old and heavy mates is probably evolutionarily advantageous.
11
RAZA, Ghulam Ali. "FOOD CONTENTS ANALYSIS OF WATERFOWL PASSING THROUGH INDUS THE RIVER AT TAUNSA, SOUTH PUNJAB, PAKISTAN". Agrobiological Records 12 (giugno 2023): 9–21. http://dx.doi.org/10.47278/journal.abr/2023.010.
Testo completoAbstract (sommario):
A study was carried out to assess the food composition of migratory waterfowl in Bet Makwal Kalan, near the Head Taunsa Barrage, along the River Indus passage. Migratory water birds are thought to be important components in dispersal of total living entity especially seeds due to their proclivity for extensive relocations. They might be found in large numbers in the muddy sections. Migratory water birds are important components of total plant dispersal due to their proclivity for making extensive migrations. A sum of 459 gizzard samples was collected, during their Fall migration, relating to 10 Waterfowl species i.e. Northern Pintail (n=56), Eurasian Wigeon (n=17), Garganay (n=07), Mallard (n=02), Northern Shoveler (n=22), Common Teal (n=129), Gadwall (n=158), Tufted Duck (n=04), Common Pochard (n=29) and Ferruginous Duck (n=34). During their winter migration, the Waterfowl species picked plants over animals as their primary source of sustenance when travelling through Taunsa. Food research revealed that all 10 species of birds consumed large amounts of seeds. Out of ten duck species, two plant species (Naias marina and Potamogeton pusillus) consistently ranked among the top seeds ingested by six of the duck species (Eurasian Wigeon, Garganey, Mallard, Gadwall, Tufted Duck, and Common Pochard). Whereas the Northern Pintail, Northern Shoveler, Common Teal, and Ferruginous Duck have been found to consume large amounts of seeds from Potamogeton pectinatus and Poligonum spp. It was determined that molluscans and crustaceans residues were found to be well-represented in the gizzard samples of ducks. The recent study also highlighted that various vegetations play vital role in wetland ecosystems as a basic wild food provider. A larger population of migrating Waterfowl yield better findings for this study, which is currently being undertaken.
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Zarubin, Boris E., Vyacheslav V. Kolesnikov, Anna V. Kozlova, Maria S. Shevnina e Alexander V. Economov. "Species structure of small game hunting in the Kirov region at the beginning of the XXI century". Agricultural Science Euro-North-East 22, n. 4 (27 agosto 2021): 597–607. http://dx.doi.org/10.30766/2072-9081.2021.22.4.597-607.
Testo completoAbstract (sommario):
An assessment of the species structure and size of small game prey for the spring and autumn-winter hunting seasons on the territory of the Kirov region was made, using a questionnaire survey based on the analysis of the prey of 3220 individuals. Small game includes such species (groups of species) as mallard, Northern shoveler, pintail, teal-whistle, teal cracker (Garganey), Eurasian wigeon, diving ducks, white-fronted goose, bean goose, wood grouse, black grouse, hazel grouse, woodcock, double snipe, snipe, corncrake, wood pigeon, turtle doves, white hare, European hare. The average index of production by species and groups of species per 1 hunter, who went hunting in the spring and autumn-winter seasons, has been calculated. The size of game catch during the spring hunting was 135.8 thousand individuals, in the autumn-winter hunting season -470 thousand individuals. The summation of the results obtained made it possible to estimate the volume of the total (annual) catch of small game in the amount of almost 606 thousand individuals. The main species are the mallard, hazel grouse, white hare, woodcock, black grouse, Eurasian wigeon, teal cracker (Garganey), Northern shoveler, wood grouse, white-fronted goose, bean goose, teal-whistle, their total share is 94.88% of the annual production of small game. The first five species can be assessed as the most massive in production (or popular), the share of each of them is over 10% of the total production, and in total they amount to 70.4%.
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Ryckman, Mason D., Kaylan Kemink, Christopher J. Felege, Brian Darby, Gregory S. Vandeberg e Susan N. Ellis-Felege. "Behavioral responses of blue-winged teal and northern shoveler to unmanned aerial vehicle surveys". PLOS ONE 17, n. 1 (19 gennaio 2022): e0262393. http://dx.doi.org/10.1371/journal.pone.0262393.
Testo completoAbstract (sommario):
Unmanned aerial vehicles (UAVs) have become a popular wildlife survey tool. Most research has focused on detecting wildlife using UAVs with less known about behavioral responses. We compared the behavioral responses of breeding blue-winged teal (Spatula discors) (n = 151) and northern shovelers (Spatula clypeata) (n = 46) on wetlands flown over with a rotary DJI Matrice 200 quadcopter and control wetlands without flights. Using a GoPro camera affixed to a spotting scope, we conducted focal individual surveys and recorded duck behaviors for 30 minutes before, during, and 30 minutes after UAV flights to determine if ducks flushed or changed in specific activities. We also conducted scan surveys during flights to examine flushing and movement on the entire wetland. Between 24 April and 27 May 2020, we conducted 42 paired (control and flown) surveys. Both teal and shovelers increased proportion of time engaged in overhead vigilance on flown wetlands from pre-flight to during flight (0.008 to 0.020 and 0.006 to 0.032 of observation time, respectively). Both species left the wetland more frequently during flights than ducks on control wetlands. Despite similarities between species, we observed marked differences in time each species spent on active (e.g., feeding, courtship, swimming), resting, and vigilant behaviors during flights. Overall, teal became less active during flights (0.897 to 0.834 of time) while shovelers became more active during this period (0.724 to 0.906 of time). Based upon scan surveys, ducks flushed in 38.1% of surveys while control wetlands only had a single (2.4%) flush during the flight time. We found launch distance was the most important predictor of whether ducks swam for cover or away from the UAV which could result in inaccurate counts. Ducks appear aware of UAVs during flights, but minimal behavioral shifts suggest negative fitness consequences are unlikely.
14
Lewis, Thomas E., e Pamela R. Garrettson. "Parasitism of a Blue-winged Teal Nest by a Northern Shoveler in South Dakota". Wilson Journal of Ornithology 122, n. 3 (settembre 2010): 612–14. http://dx.doi.org/10.1676/10-010.1.
Testo completo
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Grand, James Barry. "Nesting success of ducks on the central Yukon Flats, Alaska". Canadian Journal of Zoology 73, n. 2 (1 febbraio 1995): 260–65. http://dx.doi.org/10.1139/z95-030.
Testo completoAbstract (sommario):
Nesting success was studied at Canvasback Lake and Mallard Lake on the Yukon Flats in interior Alaska in 1989–1991. Simple estimates of nesting success were computed using two techniques that assume a constant daily survival rate (DSR). Maximum-likelihood estimates of nesting success for all ducks, assuming constant DSR, ranged among years and sites from near zero to 12%. However, DSRs were not constant but increased with nest age and initiation date (R2 = 0.42, P = 0.0001). Nesting success was near zero for nests initiated 1–10 May and increased to 100% for nests initiated after 30 June. Therefore, species nesting in early to mid season, such as Mallard (Anas platyrhynchos), Northern Pintail (A. acuta), and Northern Shoveler (A. clypeata), had lower success than later nesting species such as Green-winged Teal (A. crecca) and Lesser Scaup (Aythya affinis). In 1990 and 1991, combined nesting success of all species, allowing for variation in DSR with nest initiation date and age of nest, was 12.50%.
16
Touarfia, Moundji, e Nadhra Boukrouma. "Breeding ecology of the northern shoveller (Spatula clypeata) in Tiffech Lake (Souk Ahras, Northeastern Algeria)". Acta Musei Silesiae, Scientiae Naturales 71, n. 2 (1 maggio 2022): 97–104. http://dx.doi.org/10.2478/cszma-2022-0005.
Testo completoAbstract (sommario):
Abstract The breeding behavior of Northern Shoveler (Spatula clypeata) was studied from January 2019 to March 2021 in Tiffech lake, an artificial wetland, in Souk Ahras Province, Northeastern Algeria. On this ecosystem, egg-laying occurred from earlier January to mid-March. In this study, there was a positive correlation between the egg-laying period and the number of active nests. The mean incubation period was 36.0 days. Clutches started later in the season and had a shorter incubation duration than early clutches. Hatching success amounted to 79.2% (n= 52 nests) and hatching success from eggs 37.6. In this study we measured water depth to control differences in habitats availability for the species, we speculate that differences in food abundance, water depth, and behavioral strategies during the breeding season collectively influence the selection of breeding habitat.
17
Guillemain, Matthieu, Herve Fritz, Noël Guillon e Noel Guillon. "Foraging Behavior and Habitat Choice of Wintering Northern Shoveler in a Major Wintering Quarter in France". Waterbirds: The International Journal of Waterbird Biology 23, n. 3 (2000): 353. http://dx.doi.org/10.2307/1522173.
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House, Deborah J. "Fall Waterfowl Use of Bridgeport Reservoir, Mono County, California". Western Birds 52, n. 4 (1 novembre 2021): 278–95. http://dx.doi.org/10.21199/wb52.4.1.
Testo completoAbstract (sommario):
Aerial surveys from 2003 to 2019 documented the abundance of waterfowl at Bridgeport Reservoir in Mono County, California, from September through mid-November. Waterfowl totals at Bridgeport Reservoir averaged 33,106 ± 4050 (standard error) in the fall. Annual peak counts averaged 10,474 ± 1349, ranging from a low of 2583 in 2014 to the highest single-day count of 23,150 in 2005. Bridgeport Reservoir is a man-made water body in the intermountain West that waterfowl use primarily a mid-migration stopover site, with peak numbers occurring in September. The dominant waterfowl species, the Northern Shoveler (Spatula clypeata), Gadwall (Mareca strepera), Mallard (Anas platyrhynchos), Northern Pintail (A. acuta), and Green-winged Teal (A. crecca), showed both unimodal and bimodal migration chronologies. Regional drought, as indicated by the Palmer drought severity index, combined with a downward trend in waterfowl numbers explained 61.4% of annual variation in fall waterfowl totals. These data may allow future assessment of change in waterfowl abundance at Bridgeport Reservoir in the context of local or regional conditions, and as influenced by climate change.
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Lamont, Myles M. "New avian breeding records for Kugluktuk, Nunavut". Canadian Field-Naturalist 132, n. 3 (11 aprile 2019): 254–60. http://dx.doi.org/10.22621/cfn.v132i3.1903.
Testo completoAbstract (sommario):
New breeding records for 10 species of tundra and boreal nesting birds were documented near the community of Kugluktuk (Nunavut, Canada) over the course of the 2015 and 2016 breeding seasons and incidentally in 2017 and 2018. These species include American Wigeon (Mareca americana), Mallard (Anas platyrhynchos), Northern Shoveler (Anas clypeata), Green-winged Teal (Anas carolinensis), Greater Scaup (Aythya marila), Say’s Phoebe (Sayornis saya), Canada Jay (Perisoreus canadensis), Greycheeked Thrush (Catharus minimus), Yellow-rumped Warbler (Setophaga coronata), and Dark-eyed Junco (Junco hyemalis). Previously unpublished breeding evidence for Bald Eagle (Haliaeetus leucocephalus) is also discussed along with suspected breeding of Barn Swallow (Hirundo rustica), Bohemian Waxwing (Bombycilla garrulus), White-throated Sparrow (Zonotrichia albicollis), and Pine Grosbeak (Pinicola enucleator). These records represent the first described breeding occurrences for these species in the Kitikmeot region, or new records for the mainland of Nunavut. A lack of historical ornithological survey effort in this area has likely led to the diversity of these previously unrecorded breeding observations. These results highlight the need to increase geographic coverage of bird surveys in northern Canada to more accurately delineate the northern limit of breeding ranges and suggest that further formal survey effort will undoubtedly lead to additional new breeding records.
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Padilla-Aguilar, Patricia, Evangelina Romero-Callejas, David Osorio-Sarabia, José Ramírez-Lezama, Nohemi Cigarroa-Toledo, Carlos Machain-Williams, Carlos Manterola e Heliot Zarza. "Detection and Molecular Identification of Sarcocystis rileyi (Apicomplexa: Sarcocystidae) From a Northern Shoveler (Anas clypeata) in Mexico". Journal of Wildlife Diseases 52, n. 4 (ottobre 2016): 931–35. http://dx.doi.org/10.7589/2016-01-004.
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St. James, Elizabeth A., Michael L. Schummer, Richard M. Kaminski, Edward J. Penny e L. Wesley Burger. "Effect of Weekly Hunting Frequency on Rate of Ducks Harvested". Journal of Fish and Wildlife Management 6, n. 1 (1 settembre 2014): 247–54. http://dx.doi.org/10.3996/012014-jfwm-009.
Testo completoAbstract (sommario):
Abstract Waterfowl hunting is important culturally and economically in North America. Few studies have evaluated the relationship between weekly hunting frequency and rate of ducks harvested. We evaluated the effect of hunting 2 or 4 d/wk on rate of ducks harvested on three Mississippi Wildlife Management Areas, USA, during three waterfowl hunting seasons, December–January 2008–2011. Harvest of all ducks combined, mallard Anas platyrhynchos, northern shoveler Anas clypeata, or green-winged teal Anas crecca per hunter day did not differ between areas hunted 2 or 4 d/wk, but increased with hours spent afield. We suggest Wildlife Management Areas may be hunted 4 d/wk without reducing duck harvest per hunter day. We recommend continued evaluations of weekly hunting frequency on rate of ducks harvested to sustain science-guided management of waterfowl hunting on Mississippi public lands and elsewhere.
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Shirkey, Brendan T., John W. Simpson e Michael A. Picciuto. "A 137-Year History of the Summer Avian Community at the Winous Point Marsh, Port Clinton, Ohio, USA". Ohio Journal of Science 119, n. 2 (31 ottobre 2019): 48. http://dx.doi.org/10.18061/ojs.v119i2.6649.
Testo completoAbstract (sommario):
The Winous Point Marsh Conservancy and the Winous Point Shooting Club, with landholdings in both Sandusky and Ottawa Counties, Ohio, has completed a survey of the summer resident bird population on the property 4 times spanning 137 years. Although achieving a true census is unrealistic, these surveys have provided a unique, long-term history of changes in the avian community in northwest Ohio since the 1880s. Surveys were completed in 1880, 1930, 1960, and 2017. Draining and deforestation of the wetlands in northwest Ohio, by the late 1870s, resulted in the loss of many forested-wetland dependent species such as Blue-gray Gnatcatcher (Polioptila caerulea), Solitary Sandpiper (Tringa solitaria), and Northern Waterthrush (Parkesia noveboracensis) after the 1880 survey. Intensification of agricultural practices after the 1930 survey likely resulted in the loss of the early successional habitat that was associated with smaller, less intensive, agricultural practices and consequently the loss of many grassland nesting species such as Bobolink (Dolichonyx oryzivorus), Eastern Meadowlark (Sturnella magna), Northern Bobwhite (Colinus virginianus), Blue-winged Teal (Anas discors), Northern Pintail (Anas acuta), and Northern Shoveler (Anas clypeata). Several new species were documented during the 2017 survey including Osprey (Pandion haliaetus), Sandhill Crane (Antigone canadensis), Trumpeter Swan (Cygnus buccinator), and American White Pelican (Pelecanus erythrorhynchos). This long-term dataset provides a unique opportunity to investigate the avian immigration, extirpation, and recolonization of a specific site over the past 137 years, providing insight into how landscape-level habitat changes affected the avian community.
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Khemis, Mohamed Dhaya El-Hak, Okba Boumaaza, Ettayib Bensaci, Hichem Amari, Khayreddine Boucherit, Elafri Ali, Saâd Hanane, Zihad Bouslama e Moussa Houhamdi. "Diurnal behavior and pairing chronology of the Northern Shoveler wintering in unprotected remnant wetlands of north-eastern Algeria". Zoology and Ecology 27, n. 1 (2 gennaio 2017): 11–18. http://dx.doi.org/10.1080/21658005.2016.1278321.
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St. James, Elizabeth A., Michael L. Schummer, Richard M. Kaminski, Edward J. Penny e L. Wesley Burger. "Effect of Weekly Hunting Frequency on Duck Abundances in Mississippi Wildlife Management Areas". Journal of Fish and Wildlife Management 4, n. 1 (1 giugno 2013): 144–50. http://dx.doi.org/10.3996/042012-jfwm-034.
Testo completoAbstract (sommario):
Abstract Management of waterfowl habitat and hunting frequency is important to sustain hunting opportunities in Mississippi and elsewhere in North America. Managers have limited scientific information regarding the effect of weekly hunting frequency on waterfowl abundance for use in developing hunting plans for public hunting areas. We divided the hunted portions of three Mississippi Wildlife Management Areas into two treatments to evaluate the effect of hunting 2 versus 4 d/wk on duck abundance. Abundance of all ducks, mallard Anas platyrhynchos, northern shoveler Anas clypeata, and green-winged teal Anas crecca were not detectably different between weekly hunting frequencies. Sanctuary use increased approximately 30% during the first 1.25 h after sunrise regardless of hunting disturbance being present or absent. Our results indicate that duck abundance did not increase with increased rest days at Wildlife Management Areas, suggesting these areas may be hunted 4 d/wk without significantly decreasing duck abundance. Sanctuaries were used daily and may be vital to attract and retain ducks on Wildlife Management Areas.
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Raquel, A. J., J. H. Devries, D. W. Howerter, R. T. Alisauskas, S. W. Leach e R. G. Clark. "Timing of nesting of upland-nesting ducks in the Canadian prairies and its relation to spring wetland conditions". Canadian Journal of Zoology 94, n. 8 (agosto 2016): 575–81. http://dx.doi.org/10.1139/cjz-2016-0021.
Testo completoAbstract (sommario):
Timing of breeding varies among waterfowl species and individuals, with strong effects on reproductive success, and may be related to habitat quality. Here, we analyse the start, span, and end of the nesting season for nine upland-nesting duck species at 166 Canadian Prairie–Parkland sites over 34 years to better characterize nesting patterns and test whether and how species respond to May pond abundances. Nesting metrics were compared between single-site versus multiple-site studies over 7 years to evaluate the effects of spatial scale and methodology. Strong, consistent differences in start of nesting were found among duck species, being earliest for Northern Pintail (Anas acuta L., 1758) and Mallard (Anas platyrhynchos L., 1758), followed by Northern Shoveler (Anas clypeata L., 1758), American Green-winged Teal (Anas crecca carolinensis Gmelin, 1789 = Anas carolinensis Gmelin, 1789), Blue-winged Teal (Anas discors L., 1766), American Wigeon (Anas americana Gmelin, 1789), Gadwall (Anas strepera L., 1758), and lastly by Lesser Scaup (Aythya affinis (Eyton, 1838)) and White-winged Scoter (Melanitta fusca deglandi (Bonaparte, 1850)). Span and end of nesting were related to May pond abundances, but the strength of these relationships varied among species, presumably reflecting the flexible (re-)nesting potential of individuals of some species in response to wetland-habitat quality.
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El Bakary, Neveen, Abu-Almaaty H., Sarah Ahmed e Mohamed Hassan. "Comparative Morphological, Ultrastructural and Histological Studies on the Tongue of Eurasian Wigeon )Anas penelope) and Northern Shoveler )Anas clypeata)". Egyptian Academic Journal of Biological Sciences, B. Zoology 8, n. 1 (1 agosto 2016): 87–98. http://dx.doi.org/10.21608/eajbsz.2016.13466.
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Van Der Winden, Jan, Alhaji Siaka, Kenneth Gbenga, Sjoerd Dirksen e Martin Poot. "First records for Sierra Leone of Eurasian Spoonbill Platalea Leucorodia, Northern Shoveler Anas clypeata and Terek Sandpiper Xenus cinereus". Bulletin of the African Bird Club 15, n. 1 (marzo 2008): 108–9. http://dx.doi.org/10.5962/p.309847.
Testo completo
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Nabil, Nehal M., Ahmed M. Erfan, Maram M. Tawakol, Naglaa M. Haggag, Mahmoud M. Naguib e Ahmed Samy. "Wild Birds in Live Birds Markets: Potential Reservoirs of Enzootic Avian Influenza Viruses and Antimicrobial Resistant Enterobacteriaceae in Northern Egypt". Pathogens 9, n. 3 (6 marzo 2020): 196. http://dx.doi.org/10.3390/pathogens9030196.
Testo completoAbstract (sommario):
Wild migratory birds are often implicated in the introduction, maintenance, and global dissemination of different pathogens, such as influenza A viruses (IAV) and antimicrobial-resistant (AMR) bacteria. Trapping of migratory birds during their resting periods at the northern coast of Egypt is a common and ancient practice performed mainly for selling in live bird markets (LBM). In the present study, samples were collected from 148 wild birds, representing 14 species, which were being offered for sale in LBM. All birds were tested for the presence of AIV and enterobacteriaceae. Ten samples collected from Northern Shoveler birds (Spatula clypeata) were positive for IAV and PCR sub-typing and pan HA/NA sequencing assays detected H5N8, H9N2, and H6N2 viruses in four, four, and one birds, respectively. Sequencing of the full haemagglutinin (HA) gene revealed a high similarity with currently circulating IAV in Egypt. From all the birds, E. coli was recovered from 37.2% and Salmonella from 20.2%, with 66–96% and 23–43% isolates being resistant to at least one of seven selected critically important antimicrobials (CIA), respectively. The presence of enzootic IAV and the wide prevalence of AMR enterobacteriaceae in wild birds highlight the potential role of LBM in the spread of different pathogens from and to wild birds. Continued surveillance of both AIV and antimicrobial-resistant enterobacteriaceae in wild birds’ habitats is urgently needed.
29
Gál, Erika, László Daróczi-Szabó e Márta Daróczi-Szabó. "Bird Bone Remains from Two Medieval Settlements in Debrecen (Eastern Hungary)". Acta Archaeologica Academiae Scientiarum Hungaricae 71, n. 1 (1 giugno 2020): 199–218. http://dx.doi.org/10.1556/072.2020.00008.
Testo completoAbstract (sommario):
This paper presents results on three medieval avian bone assemblages found at Debrecen-Monostor-erdő and Debrecen-Tócó-part, respectively. Domestic chicken yielded most of the bird remains to evidence the exploitation of adult birds for egg production and flock maintenance in particular. In addition, feather harvesting and fat production could have been the target of goose (and possibly duck) husbandry. Although the goose bone sizes resemble the greylag goose, the keeping of an unimproved form of domestic goose rather than the hunting of the wild ancestor is suggested by the structure of the assemblage and the presence of healed bones. Wild birds seem to have been rarely consumed by the settlers of the two villages, but the feathers or wings or carcasses of diurnal birds of prey and crows may have been used for special purposes. Either killed for their symbolic meaning or only persecuted for protecting the backyard animals, the red kite (Milvus milvus) and the hen harrier (Circus cyaneus) represent new species for the medieval avifauna of Hungary, similarly to the Northern shoveler (Anas clypeata) and the Northern lapwing (Vanellus vanellus) that could have been hunted in the marshy environment provided by the Tócó creek. Moreover, the use of trained saker falcon (Falco cherrug) for hawking cannot be excluded either. In addition to the exploitation of birds for the abovementioned goods and values, two needle cases made from goose bones evidence the utilization of their skeletal parts as raw material for producing artefacts as well.
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Fleskes, Joseph P., Andrew M. Ramey, Andrew B. Reeves e Julie L. Yee. "Body Mass, Wing Length, and Condition of Wintering Ducks Relative to Hematozoa Infection". Journal of Fish and Wildlife Management 8, n. 1 (1 febbraio 2017): 89–100. http://dx.doi.org/10.3996/082016-jfwm-063.
Testo completoAbstract (sommario):
Abstract Waterfowl managers lack information regarding factors that may be reducing the positive response of waterfowl body condition to habitat improvements. Protozoan blood parasites (i.e., hematozoa) are commonly found in birds and have been related to reduced body mass, wing length, and body condition. We studied relationships between 12 measures of hematozoa infection and body mass, wing length, and body mass divided by wing length (i.e., body condition index) of the five most common duck species (northern pintail [Anas acuta], mallard [A. platyrhynchos], green-winged teal [A. crecca], American wigeon [A. americana], northern shoveler [A. clypeata]) wintering in the Central Valley of California during October 2006–January 2007. After accounting for variation due to species, age–sex cohort, Central Valley region, and month, wing length, body mass, and body condition index were found to be negatively related to infection by Leucocytozoon and by “any hematozoa” but not related to infection by only Plasmodium or Haemoproteus, or coinfections of greater than one genus or parasite haplotype (albeit few ducks had Plasmodium or Haemoproteus infection or coinfections). Evidence of a negative relationship with infection was stronger for body mass and body condition index than for wing length and indicated that the relationships varied among species, age–sex cohorts, regions, and months. Compared with uninfected ducks, hematozoa-infected duck body mass, wing length, and body condition index was −1.63% (85% CI = −2.79% to −0.47%), −0.12% (−0.41% to 0.17%), and −1.38% (−2.49% to −0.26%), respectively. Although seemingly small, the −1.63% difference in body mass represents a large percentage (e.g., 38% for northern pintail) of the observed increase in wintering duck body mass associated with Central Valley habitat improvements. Because infection prevalence and relationship to body condition might change over time because of climate or other factors, tracking hematozoa infection prevalence might be important to inform and accurately assess the effect of conservation programs designed to improve waterfowl body condition.
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Arzel, C., J. Elmberg e M. Guillemain. "A flyway perspective of foraging activity in Eurasian Green-winged Teal, Anas crecca crecca". Canadian Journal of Zoology 85, n. 1 (gennaio 2007): 81–91. http://dx.doi.org/10.1139/z06-201.
Testo completoAbstract (sommario):
Time–activity budgets in the family Anatidae are available for the wintering and breeding periods. We present the first flyway-level study of foraging time in a long-distance migrant, the Eurasian Green-winged Teal, Anas crecca crecca L., 1758 (“Teal”). Behavioral data from early and late spring staging, breeding, and molting sites were collected with standardized protocols to explore differences between the sexes, seasons, and diel patterns. Teal foraging activity was compared with that of the Mallard, Anas platyrhynchos L., 1758 and Northern Shoveler, Anas clypeata L., 1758, and the potential effects of duck density and predator-caused disturbance were explored. In early spring, foraging time was moderate (50.5%) and mostly nocturnal (45%). It increased dramatically in all three species at migration stopovers and during molt, mostly because of increased diurnal foraging, while nocturnal foraging remained fairly constant along the flyway. These patterns adhere to the “income breeding” strategy expected for this species. No differences between the sexes were recorded in either species studied. Teal foraging time was positively correlated with density of Teal and all ducks present, but negatively correlated with predator disturbance. Our study suggests that Teal, in addition to being income breeders, may also be considered as income migrants; they find the energy necessary to migrate at staging sites along the flyway.
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Marchowski, Dominik, Łukasz Jankowiak, Łukasz Ławicki e Dariusz Wysocki. "Waterbird counts on large water bodies: comparing ground and aerial methods during different ice conditions". PeerJ 6 (17 luglio 2018): e5195. http://dx.doi.org/10.7717/peerj.5195.
Testo completoAbstract (sommario):
The aerial and ground methods of counting birds in a coastal area during different ice conditions were compared. Ice coverage of water was an important factor affecting the results of the two methods. When the water was ice-free, more birds were counted from the ground, whereas during ice conditions, higher numbers were obtained from the air. The first group of waterbirds with the smallest difference between the two methods (average 6%) contained seven species: Mute Swan Cygnus olor, Whooper Swan Cygnus cygnus, Greater Scaup Aythya marila, Tufted Duck Aythya fuligula, Common Goldeneye Bucephala clangula, Smew Mergellus albellus and Goosander Mergus merganser; these were treated as the core group. The second group with a moderate difference (average 20%) included another six species: Mallard Anas platyrhynchos, Eurasian Wigeon Mareca penelope, Common Pochard Aythya ferina, Great Crested Grebe Podiceps cristatus and Eurasian Coot Fulica atra. The third group with a large difference (average 85%) included five species, all of the Anatini tribe: Gadwall Mareca strepera, Northern Pintail Anas acuta, Northern Shoveler Spatula clypeata, Eurasian Teal Anas crecca and Garganey Spatula querquedula. During ice conditions, smaller numbers of most species were counted from the ground. The exception here was Mallard, more of which were counted from the ground, but the difference between two methods was relatively small in this species (7.5%). Under ice-free conditions, both methods can be used interchangeably for the most numerous birds occupying open water (core group) without any significant impact on the results. When water areas are frozen over, air counts are preferable as the results are more reliable. The cost analysis shows that a survey carried out by volunteer observers (reimbursement of travel expenses only) from the land is 58% cheaper, but if the observers are paid, then an aerial survey is 40% more economical.
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NAVEDO, JUAN G., JOSÉ A. MASERO, JUAN M. SÁNCHEZ-GUZMÁN, JOSÉ M. ABAD-GÓMEZ, JORGE S. GUTIÉRREZ, ESTHER G. SANSÓN, AUXILIADORA VILLEGAS, EMILIO COSTILLO, CASIMIRO CORBACHO e RICARDO MORÁN. "International importance of Extremadura, Spain, for overwintering migratory dabbling ducks: a role for reservoirs". Bird Conservation International 22, n. 3 (5 dicembre 2011): 316–27. http://dx.doi.org/10.1017/s0959270911000311.
Testo completoAbstract (sommario):
SummaryMany migratory waterbird populations are in decline and loss of natural wetlands is one of the main causes. However, some species may respond positively to artificial wetland recreation. In Extremadura (south-west Europe), several large reservoirs were created for irrigation since the 1960s and some comparatively small reservoirs were built from the late 1990s onwards close to rice fields. Here we analyse the abundance of wintering dabbling ducks (Anas spp.) in Extremadura before (1991–1994) and after (2007–2010) the creation of these new reservoirs in order to address the current importance of the area for this guild within the East Atlantic Flyway (EAF). A mean of 25,277 dabbling ducks wintered in the study area during 1991–1994, increasing to 46,163 individuals during 2007–2010. After controlling for environmental variables, Northern Pintail Anas acuta, Common Teal A. crecca and Northern Shoveler A. clypeata experienced significant increases in the area between both periods, and only Eurasian Wigeon A. penelope suffered a significant decrease. Mallard A. platyrhynchos and Gadwall A. strepera populations did not show any significant trend. The large older reservoirs experienced overall population decreases between the two periods, with four new reservoirs holding more than 35,000 wintering dabbling ducks. Our results reflect an overall improvement in habitat conditions, driven by the creation of reservoirs near to rice fields that could have resulted in a partial redistribution of wintering dabbling ducks in the EAF. The area emerges as one of the most important wintering sites for dabbling ducks in southern Europe, regularly exceeding two of the Ramsar Convention criteria for the conservation of several populations. The protection of these new reservoirs by legal mechanisms would guarantee the existence of a large functional wetland area, which could also mitigate the loss of natural wetlands for populations using the EAF.
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Arikawa, Genki, Yoshinori Fujii, Maiku Abe, Ngan Thi Mai, Shuya Mitoma, Kosuke Notsu, Huyen Thi Nguyen et al. "Meteorological factors affecting the risk of transmission of HPAI in Miyazaki, Japan". Veterinary Record Open 6, n. 1 (settembre 2019): e000341. http://dx.doi.org/10.1136/vetreco-2019-000341.
Testo completoAbstract (sommario):
Highly pathogenic avian influenza (HPAI) outbreaks engender a severe economic impact on the poultry industry and public health. Migratory waterfowl are considered the natural hosts of HPAI virus, and HPAI viruses are known to be transmitted over long distances during seasonal bird migration. Bird migration is greatly affected by the weather. Many studies have shown the relationship between either autumn or spring bird migration and climate. However, few studies have shown the relationship between annual bird migration and annual weather. This study aimed to establish a model for the number of migratory waterfowl involved in HPAI virus transmission based on meteorological data. From 136 species of waterfowl that were observed at Futatsudate in Miyazaki, Japan, from 2008 to 2016, we selected potential high-risk species that could introduce the HPAI virus into Miyazaki and defined them as ‘risky birds’. We also performed cluster analysis to select meteorological factors. We then analysed the meteorological data and the total number of risky birds using a generalised linear mixed model. We selected 10 species as risky birds: Mallard (Anas platyrhynchos), Northern pintail (Anas acuta), Eurasian wigeon (Anas penelope), Eurasian teal (Anas crecca), Common pochard (Aythya ferina), Eurasian coot (Fulica atra), Northern shoveler (Anas clypeata), Common shelduck (Tadorna tadorna), Tufted duck (Aythya fuligula) and Herring gull (Larus argentatus). We succeeded in clustering 35 meteorological factors into four clusters and identified three meteorological factors associated with their migration: (1) the average daily maximum temperature; (2) the mean value of global solar radiation and (3) the maximum daily precipitation. We thus demonstrated the relationship between the number of risky birds and meteorological data. The dynamics of migratory waterfowl was relevant to the risk of an HPAI outbreak, and our data could contribute to cost and time savings in strengthening preventive measures against epidemics.
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Breed, William, John Hatch, Colin Rogers, Harry Roberts e Ingrid Ahmer. "Effects of rainfall in the arid zone on waterbird abundance at a wastewater treatment plant in coastal South Australia". Australian Field Ornithology 40 (2023): 59–69. http://dx.doi.org/10.20938/afo40059069.
Testo completoAbstract (sommario):
We investigated which species of waterbirds at Bolivar, a wastewater treatment plant in Metropolitan Adelaide, South Australia, are likely to have been immigrants from the ephemeral wetlands in the arid zone. To do this, we compared the abundance of waterbird species observed at Bolivar during the dry period in the eastern arid zone of late 2018 and 2019 with that during the subsequent wet period 2020–2022. Pink-eared Duck Malacorhynchus membranaceus, Grey Teal Anas gracilis, Australasian Shoveler Spatula rhynchotis, Hardhead Aythya australis and Blue-billed Duck Oxyura australis were all more abundant during the arid-zone dry period. By contrast, Australian Shelduck Tadorna tadornoides, Eurasian Coot Fulica atra and Black Swan Cygnus atratus showed increased abundance in spring and early summer in all years, with no marked differences between the dry and wet periods in the arid zone. Wader species that breed in the Northern Hemisphere – Sharp-tailed Sandpiper Calidris acuminata and Red-necked Stint C. ruficollis – also tended to be more abundant during the arid-zone dry year, as did Red-necked Avocet Recurvirostra novaehollandiae, whereas Pied Stilt Himantopus leucocephalus tended to be more abundant in the arid-zone wet years, with breeding by this species taking place in spring. These data suggest that Bolivar is a critically important conservation site for waterbirds and that various species use this location as a refuge during dry times in the arid zone of eastern Australia.
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Drever, Mark C., Andreas Wins-Purdy, Thomas D. Nudds e Robert G. Clark. "Decline of Duck Nest Success Revisited: Relationships With Predators and Wetlands in Dynamic Prairie Environments". Auk 121, n. 2 (1 aprile 2004): 497–508. http://dx.doi.org/10.1093/auk/121.2.497.
Testo completoAbstract (sommario):
Abstract Covariation among factors that may affect nest success of dabbling ducks in the Prairie Pothole Region of North America (e.g. productivity of upland and wetland habitat related to climate variation, and duck and predator densities) often confounds efforts to interpret the effect of any individual factor. A comparison of nest success of dabbling ducks at sites with and without predator management provided an opportunity to separate the effect of predation pressure from other factors because predator management has occurred over a range of climatic conditions. We updated an existing study on temporal trends of nest success for prairie ducks in the Prairie Pothole Region of North America by compiling recent estimates of nest success for five species of dabbling ducks (Mallard [Anas platyhrynchos], Northern Pintail [A. acuta], Northern Shoveler [A. clypeata], Blue-winged Teal [A. discors], and Gadwall [A. strepera]). In addition, we compared trends of nest success at unmanaged sites and sites where nest predators were excluded or removed. We used pond density calculated from annual surveys for breeding waterfowl as an index of upland and wetland productivity and a correlate of predator and duck density. At unmanaged sites, the best approximating local regression model suggested that, rather than having undergone a monotonic decline, average nest success has fluctuated through time, although those changes do not appear to be associated with changes in pond density. At sites where predators were excluded, nest success did not vary with time but varied positively with pond density in the previous year, although that effect was tempered by high pond density in the year of observation. At sites where predators were removed but could emigrate back into study plots, nest success varied widely over time and we found no evidence of an effect of pond density. We show that nest success of dabbling ducks is higher under predator management than at sites without predator management, and that this relationship varies with climatic conditions, possibly related to complex interactions within and among duck species, their predators, and their prey.
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KIRIHARA, Masashi. "The first record of a hybrid individual between Northern Shoveler Anas clypeata and Gadwall A. strepera for Japan at Yatsu tidal flat, Chiba Prefecture". Japanese Journal of Ornithology 70, n. 1 (23 aprile 2021): 61–65. http://dx.doi.org/10.3838/jjo.70.61.
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McDuie, Fiona, Michael L. Casazza, David Keiter, Cory T. Overton, Mark P. Herzog, Cliff L. Feldheim e Joshua T. Ackerman. "Moving at the speed of flight: dabbling duck-movement rates and the relationship with electronic tracking interval". Wildlife Research 46, n. 6 (2019): 533. http://dx.doi.org/10.1071/wr19028.
Testo completoAbstract (sommario):
Abstract Context Effective wildlife management requires information on habitat and resource needs, which can be estimated with movement information and modelling energetics. One necessary component of avian models is flight speeds at multiple temporal scales. Technology has limited the ability to accurately assess flight speeds, leading to estimates of questionable accuracy, many of which have not been updated in almost a century. Aims We aimed to update flight speeds of ducks, and differentiate between migratory and non-migratory flight speeds, a detail that was unclear in previous estimates. We also analysed the difference in speeds of migratory and non-migratory flights, and quantified how data collected at different temporal intervals affected estimates of flight speed. Methods We tracked six California dabbling duck species with high spatio-temporal resolution GPS–GSM transmitters, calculated speeds of different flight types, and modelled how estimates varied by flight and data interval (30min to 6h). Key results Median migratory speeds were faster (but non-significant) for the larger mallard (Anas platyrhynchos; 82.5kmh–1), northern pintail (Anas acuta; 79.0kmh–1) and gadwall (Mareca strepera; 70.6kmh–1), than the smaller-bodied northern shoveler (Spatula clypeata; 65.7kmh–1), cinnamon teal (Spatula cyanoptera; 63.5kmh–1) and American wigeon (Mareca Americana; 52kmh–1). Migratory flights were faster than non-migratory flights for all species and speeds were consistently slower with an increasing data interval. Implications The need to balance time and energy requirements may drive different speeds for migratory and non-migratory flights. Lower speeds at longer intervals are likely to be due to a greater proportion of ‘loafing’ time included in flighted segments, demonstrating that data acquired at different intervals provide a means to evaluate and estimate behaviours that influence speed estimation. Shorter-interval data should be the most accurate, but longer-interval data may be easier to collect over lengthier timeframes, so it may be expedient to trade-off a degree of accuracy in broad-scale studies for the larger dataset. Our updated flight speeds for dabbling duck species can be used to parameterise and validate energetics models, guide management decisions regarding optimal habitat distribution, and, ultimately, improve conservation management of wetlands for waterfowl.
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Lameed, GA. "Species diversity and richness of wild birds in Dagona-Waterfowl sanctuary, Nigeria". African Journal of Food, Agriculture, Nutrition and Development 12, n. 53 (3 agosto 2012): 6460–78. http://dx.doi.org/10.18697/ajfand.53.9745.
Testo completoAbstract (sommario):
The study of bird species diversity and richness in Dagona-Waterfowl Sanctuary was carried out during the midst of both early wet and late dry seasons, to provide comprehensive data on wild birds. Dagona Sanctuary is located within the BadeNguru Wetland sector. It is one of the important bird areas marked for the conservation of avifauna species in sub-Sahara region, Nigeria. Line Transect method was used to carry out birds’ survey at three different lake sites, namely: Gatsu (site:1), Mariam (site: 2) and Oxbow (site: 3). The instruments used were GarminTM 12 Global Positioning System (GPS), a pair of binoculars for bird’s identification, a field guide test- book and a 1,000 meters tape-rule. The data were tested with the Kolmogorov- Smirnov method o determine distribution level and birds’ diversity was assessed using Shannon-Weiner Diversity Index, while parametric tests were applied for all data. The results showed that bird species diversity was normally distributed in all the sites, site 2 had the highest diversity (2.74) compared to site 1: (1.84) and site 3: (1.62). Likewise, bird species richness in the area was normally distributed and significantly different (P<0.05) among the three sites. Site 1 had the highest number of bird species richness (16.36) (Species diversity is different species of birds at the site, while species richness is referring to specific species population), compared to site 2: (14.32) and site 3: (11.51). It was observed that there is a significant relationship between vegetation density and bird species diversity, because as tree density increases, diversity of bird species decreases. Therefore, there is a significant relationship between vegetation density and bird species diversity. A total of 135 bird species in 40 families was recorded during the survey. Seventy-four percent were found in site1, sixty-three percent in site 2 and seventy-one percent in site 3. The majority of wetland birds observed during this study were resident (Ardeidae family), migratory (Accipitridae family) and palearctic species (Yellow Wagtail, Warblers, Northern Shoveler and Sandpipers). It can be concluded that wild birds are good indicators of environmental condition, revealing the state of the wetland. Some sites were more disturbed, as observed in site 1 and site 3. It was, however, recommended that regular monitoring of the sites should be carried out so as to control changes in the state of the wetland ecosystem.
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MacCluskie, Margaret C., e James S. Sedinger. "Nutrient Reserves and Clutch-Size Regulation of Northern Shovelers in Alaska". Auk 117, n. 4 (1 ottobre 2000): 971–79. http://dx.doi.org/10.1093/auk/117.4.971.
Testo completoAbstract (sommario):
Abstract We determined patterns of nutrient-reserve use by female Northern Shovelers (Anas clypeata) nesting at Minto Flats, Alaska, and compared them with those of female shovelers nesting in the Prairie Pothole Region of Manitoba, Canada. Individual variation in somatic lipid was best explained by nest initiation date; females that initiated nests early had larger lipid reserves than females that delayed nest initiation. These results contrast with those from Manitoba, which showed that females used lipid reserves and stored protein during egg production. Incubating females from Alaska did not use protein or mineral reserves, but lipid reserves decreased significantly throughout incubation. Females in Alaska and Manitoba used lipid reserves similarly during incubation. We conclude that endogenous nutrient availability does not proximately limit clutch size during laying for this population of shovelers, possibly due to the high productivity of wetlands in interior Alaska and/or the long photoperiod that allow females to forage extensively. Successful completion of incubation or brood rearing may be an ultimate factor that controls clutch size for this population of shovelers.
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DuBowy, Paul J. "Long-term foraging optimization in northern shovelers". Ecological Modelling 95, n. 2-3 (febbraio 1997): 119–32. http://dx.doi.org/10.1016/s0304-3800(96)00040-3.
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Gupta, Rohtash Chand, Tirshem Kumar Kaushik e Prem Kumari Gupta. "Analysis of avian-biodiversity in rural wetland environs in Panipat district in Haryana, India". Journal of Applied and Natural Science 4, n. 2 (1 dicembre 2012): 252–57. http://dx.doi.org/10.31018/jans.v4i2.259.
Testo completoAbstract (sommario):
The present study has observed 67 species of wetland birds, belonging to, 10 orders and 18 families from rural wetland Environs in Panipat district located at a distance of 90 KMs north of Delhi on National Highway No.1 (29.39°N 76.97°E) in Haryana, India. Out of 67 species, 35 species were winter migrants, 18 residents, 10 local migrants and four species were summer migrants. Peculiar species of birds recorded in Panipat rural ponds are Painted Stork Mycteria leucocephala, White-necked Stork Ciconia episcopus, Asian openbill- Stork Anastomusoscitans, Lesser Adjutant Stork Leptoptilos javanicus, Black-necked Stork Ephippiorhynchus asiaticus, Oriental White Ibis Threskiornis melanocephalus, Black Ibis Pseudibis papillosa, Glossy Ibis Plegadis falcinellus, Eurasian Spoonbill Platalea leucorodia, Brahminy Shelduck Tadorna ferruginea, Comb Duck Sarkidiornis melanotos, Tufted Pochard Aythya fuligula and Green Sandpiper Tringa ochropus. On the other hand, familiar species include amongst others, Bar-headed Goose Anser indicus, Common Coot Fulica atra, Northern Shoveller Anas clypeata, Northern Pintail Anas acuta, Common Teal Anas crecca, Common Pochard Aythya ferina, Gadwall Anas strepera and Lesser-whistling Duck Dendrocygna javanica etc. Longest stay during winter season was demonstrated by birds like Northern Shoveller, Northern Pintail, Bar-headed Goose, Greylag Goose and Rudy Shelduck, whereas shortest winter sojourn was observed in case of Mallard, Eurasian Wigeon and Common Pochard. It is interesting to note that migratory birds like Northern Shoveller, Northern Pintail, Common Teal, Bar-headed Goose, Tufted Pochard, and Common Pochard come to Panipat rural ponds from very far off places like Central Russia, Caspian USSR, Siberia, Ladhakh and Central Asia, West and Central Asia and Siberia respectively.
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Gupta, Rohtash Chand, Tirshem Kumar Kaushik e Surjit Kumar. "An account concerning arrival and departure time of few selected winter migratory birds in Haryana rural ponds". Environment Conservation Journal 11, n. 1&2 (18 giugno 2010): 1–9. http://dx.doi.org/10.36953/ecj.2010.1201.
Testo completoAbstract (sommario):
The present study has been carried out in few selected Northern Districts of Haryana State for a period of three years w.e.f. 2005-08. Attention has been focused on winter migratory birds that sojourn in Haryana and other parts of north Haryana. These birds come to Haryana from far off places, across the rim of great Himalayas and beyond. Only eighteen birds’ departure and arrival time was recorded for study convenience. These migratory birds do not arrive in Haryana in one lot, on one date and at one time. Instead, these display a definite, pattern, decorum and time table, specific to species and even specific to place subject to varying temperature barometer.
The present study reveal that Northern Shoveller (Anas clypeata) Northern Pintail (Anas acuta) Common Teal (Anas crecca) and Gadwall (Anas strepera) arrive in October; Bar-headed Goose (Anser indicus) Graylag Goose (Anser anser) Spot billed Duck (Anas poecilorhyncha) arrive in November. As far as departure time is concerned, it is interesting to note that Mallard generally depart in February. Birds like Greylag Goose (Anser anser) Spot-billed Duck (Anas poecilorhyncha), Common Pochard (Aythya ferina), Eurasion Wigeon (Anas penelope), Tufted Pochard (Aythya fuligula) Red-crested Pochard (Rhodonessa rufina) and Rudy Shelduck (Tadorna ferruginea) departs in March every year. On the other hand, Common Coot (Fulica atra) Northern Shoveller (Anas clypeata) Northern Pintail (Anas acuta), Common Teal, (Anas crecca), Gadwall (Anas strepera) and Bar-headed Goose (Anser indicus) depart as late as April. Simultaneously, another aspect of gradual increase in number from October to December and conversely gradual decrease in number from January to February was also analyzed in case of few birds only. Greatest flocks of nearly 250 or so were in case of Northern Shoveller (Anas clypeata), Northern Pintail (Anas acuta), Common Teal (Anas crecca) and Common Coot (Fulica atra). Contrary to this, least number in a flock less than fifteen was seen in case of Bar-headed Goose (Anser indicus), Greylag Goose (Anser anser) etc.
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Gupta, Rohtash Chand, Tirshem Kumar Kaushik e Surjit Kumar. "Evaluation of the extent of wetland birds in District Kaithal, Haryana, India". Journal of Applied and Natural Science 2, n. 1 (1 giugno 2010): 77–84. http://dx.doi.org/10.31018/jans.v2i1.101.
Testo completoAbstract (sommario):
Kaithal District is comprised of 2317 Km² Sq. Km area having six blocks Viz.:Kaithal, Kalayat, Pundri, Rajound, Ghula and Siwan located at a distance of 150 Kms from New Delhi toward North West. Its geographical position lies between 29° 48' 0 N latitude and between 76° 22' 60 E longitude.The present studies were carried between 2005-2008 with the help of Zenith Camera and telelens. In all, 63 species of Wetland birds belonging to 10 Orders, 38 genera and 16 families were observed in various village ponds in Kaithal District. Out of 63 species of wetland birds, 31 are winter migratory, 9 local migratory, 3 summers migratory and 20 species are resident birds. Considering IUCN categories, Black Ibis (Pseudibis papillosa) which belongs to Biome Restricted Species (BRS) was observed in three blocks viz. Kaithal, Pundri and Rajound of Kaithal district. In addition, Spotted Greenshank (Tringa guttifer) which has been placed in endangered category of IUCN was observed as single individual. But Black Ibis (Pseudibis papillosa) was observed in a group of three to seven. Northern Shoveller (Anas clypeata), which is reportedly coming from Central Russia and Caspian Siberia has been observed in very large groups of 200-250 and virtually spotted in each and every pond in Northern Haryana. Similarly, Northern Pintail (Anas acuta), Common Teal (Anas crecca), Common Pochard (Aythya ferina), Spot-billed Duck (Anas poecilorhyncha), Lesser-whistling Teal (Dendrocygna javanica) were also seen in relatively large groups. Common Pochard (Aythya ferina) is always observed in pure groups floating in the centre of relatively big ponds. In contrast, Gadwall (Anas strepera), Northern Shoveller (Anas clypeata), Northern Pintail (Anas acuta) and Common Teal (Anas crecca), share close proximity with each other in water and are found in mixed groups. Northern Shoveller (Anas clypeata), Bar- headed Goose (Anser indicus) and Northern Pintail (Anas acuta) stay between Octobers to April. Mallard (Anas platyrhynchos) stays in winter for shortest period between December and January. Maximum wetland birds observed in Kaithal District belong to Order Charadriiformes and to family Anatidae of Order Anseriformes. Spotted Greenshank (Tringa guttifer) is the peculiar to Pundri block only, in Kaithal District.
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Ankney, C. Davison, e Alan D. Afton. "Bioenergetics of Breeding Northern Shovelers: Diet, Nutrient Reserves, Clutch Size, and Incubation". Condor 90, n. 2 (maggio 1988): 459–72. http://dx.doi.org/10.2307/1368574.
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ELARABANY, N. F., G. A. ABDALLAH e A. E. SAID. "Seasonal Variations of Steroid Hormones and Triiodothyronine Concentrations in Migratory Northern Shovelers". Journal of Experimental Zoology Part A: Ecological Genetics and Physiology 317, n. 4 (13 febbraio 2012): 216–26. http://dx.doi.org/10.1002/jez.1715.
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MacCluskie, Margaret C., e James S. Sedinger. "Incubation Behavior of Northern Shovelers in the Subarctic: A Contrast to the Prairies". Condor 101, n. 2 (maggio 1999): 417–21. http://dx.doi.org/10.2307/1370008.
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DuBowy, Paul J. "Seasonal organ dynamics in post-breeding male blue-winged teal and northern shovelers". Comparative Biochemistry and Physiology Part A: Physiology 82, n. 4 (gennaio 1985): 899–906. http://dx.doi.org/10.1016/0300-9629(85)90503-1.
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Roberts, Anthony J., e Michael R. Conover. "Breeding origins of Northern Shovelers (Anas Clypeata) wintering on the Great Salt Lake, Utah". Wilson Journal of Ornithology 127, n. 2 (giugno 2015): 233–38. http://dx.doi.org/10.1676/wils-127-02-233-238.1.
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Tietje, W. D., e J. G. Teer. "Winter Feeding Ecology of Northern Shovelers on Freshwater and Saline Wetlands in South Texas". Journal of Wildlife Management 60, n. 4 (ottobre 1996): 843. http://dx.doi.org/10.2307/3802385.
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