Academic literature on the topic 'Gulls'

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Journal articles on the topic "Gulls"

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Ryu, Hodon, John F. Griffith, Izhar U. H. Khan, Stephen Hill, Thomas A. Edge, Carlos Toledo-Hernandez, Joel Gonzalez-Nieves, and Jorge Santo Domingo. "Comparison of Gull Feces-Specific Assays Targeting the 16S rRNA Genes of Catellicoccus marimammalium and Streptococcus spp." Applied and Environmental Microbiology 78, no. 6 (January 6, 2012): 1909–16. http://dx.doi.org/10.1128/aem.07192-11.

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ABSTRACTTwo novel gull-specific quantitative PCR (qPCR) assays were developed using 16S rRNA gene sequences from gull fecal clone libraries: a SYBR green assay targetingStreptococcusspp. (gull3) and a hydrolysis TaqMan assay targetingCatellicoccus marimammalium(gull4). The objectives of this study were to compare the host specificity of a previousC. marimammaliumqPCR assay (gull2) with that of the new markers and to examine the presence of the three gull markers in environmental water samples from different geographic locations. Most of the gull fecal samples tested (n= 255) generated positive signals with the gull2 and gull4 assays (i.e., >86%), whereas only 28% were positive with gull3. Low prevalence and abundance of tested gull markers (0.6 to 15%) were observed in fecal samples from six nonavian species (n= 180 fecal samples), whereas the assays cross-reacted to some extent (13 to 31%) with other (nongull) avian fecal samples. The gull3 assay was positive against fecal samples from 11 of 15 avian species, including gull. Of the presumed gull-impacted water samples (n= 349), 86%, 59%, and 91% were positive with the gull2, the gull3, and the gull4 assays, respectively. Approximately 5% of 239 non-gull-impacted water samples were positive with the gull2 and the gull4 assays, whereas 21% were positive witg the gull3 assay. While the relatively high occurrence of gull2 and gull4 markers in waters impacted by gull feces suggests that these assays could be used in environmental monitoring studies, the data also suggest that multiple avian-specific assays will be needed to accurately assess the contribution of different avian sources in recreational waters.
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Källander, Hans. "Interspecific kleptoparasitism by four species of gull Larus spp. in South Sweden." Ornis Svecica 16, no. 3 (July 1, 2006): 127–49. http://dx.doi.org/10.34080/os.v16.22716.

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Data are presented on interspecific kleptoparasitism by Black-headed Gull Larus ridibundus, Common Gull L. canus, Herring Gull L. argentatus and Great Black-backed Gull L. marinus, collected in South Sweden from the late 1950s to the present day. The basis for the presentation is the various host species exploited by the four gull species. For each host species, information is given on species of gull kleptoparasitising it, seasonal occurrence of kleptoparasitism, details of behaviour and, when available, data on gulls’ success rates. The paper is intended as a sort of catalogue. For this reason, relevant literature is reviewed under each of the host-species headings. Gulls’ success rates varied between 55% for Black-headed Gulls and Common Gulls parasitising Northern Lapwings Vanellus vanellus, the most often observed kleptoparasitic association, and 15% on the few occasions that Black-headed Gulls parasitised Curlews Numenius arquata in grassland. When the same two gull species parasitised Common Starlings Sturnus vulgaris, their success rate varied with robbing tactic used (16% vs 45%). Beside the association of the two small gull species with Lapwings and Golden Plovers Pluvialis apricaria, the most frequently observed associations were those of Herring Gulls with Common Eiders Somateria mollissima and Great Black-backed Gulls and Herring Gulls with diving fish-eaters (Great Cormorant Phalacrocorax carbo, mergansers Mergus spp.). Kleptoparasitism often occurred during periods of food scarcity, being most common in harsh winter conditions (the two large gull species) and during cold spells in early spring (some associations of the two small gull species). As in other studies, gulls’ success rate was strongly dependent on the size of hosts’ prey, and thus, normally on handling time. It is suggested that success rate can often be used as a substitute for profitability in studies of kleptoparasitism.
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Coulson, Ruth, and Graeme Coulson. "Population change among Pacific, kelp and silver gulls using natural and artificial feeding sites in south-eastern Tasmania." Wildlife Research 25, no. 2 (1998): 183. http://dx.doi.org/10.1071/wr97027.

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The kelp gull, Larus dominicanus, which is widely distributed around the southern hemisphere, has become established in Australia only in the past half-century. The greatest numbers of kelp gulls in Australia are now found in south-eastern Tasmania in sympatry with the two endemic species, the morphologically similar Pacific gull, L. pacificus, and the smaller silver gull, L. novaehollandiae. We examined populations of the three species in this area. We surveyed large refuse tips and specific shoreline sites in the Hobart area regularly during the winter months in 1981 and again in 1992, recording numbers of each species, and age classes of kelp and Pacific gulls. Between the two survey periods, the number of Pacific gulls and the total number of all gulls present at refuse tips remained unchanged. There was, however, a marked increase in the number of kelp gulls at tips, equivalent to an annual rate of increase of 22.8%, and a corresponding decrease in the number of silver gulls. Kelp gulls of all ages were over-represented at refuse tips, while adult Pacific gulls fed preferentially at more natural shoreline sites. At shoreline sites, adult Pacific gulls appeared to exclude kelp gulls from small bays in 1981, but kelp gulls were present in most of these bays eleven years later. Reducing access to food at refuse tips may be an effective means of controlling the kelp gull population in this area.
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Massaro, Melanie, John W. Chardine, Ian L. Jones, and Gregory J. Robertson. "Delayed capelin (Mallotus villosus) availability influences predatory behaviour of large gulls on black-legged kittiwakes (Rissa tridactyla), causing a reduction in kittiwake breeding success." Canadian Journal of Zoology 78, no. 9 (September 1, 2000): 1588–96. http://dx.doi.org/10.1139/z00-085.

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During 1998 and 1999, the impact of predation by herring gulls (Larus argentatus) and great black-backed gulls (Larus marinus) on breeding success of black-legged kittiwakes (Rissa tridactyla) at Gull Island, Witless Bay, southeastern Newfoundland, was quantified in relation to the timing of the annual arrival of capelin (Mallotus villosus) to spawn. The frequency of predation attempts by large gulls on kittiwakes was compared among three periods: before the mean hatching date for herring gulls, between the mean hatching date for herring gulls and the arrival of the capelin, and following capelin arrival. The frequency varied significantly among the three periods, being highest after gull chicks hatched but before the capelin arrived. The frequency of gull predation was significantly correlated with the percentage of kittiwake eggs and chicks that disappeared each week. We estimated that 43 and 30% of kittiwake eggs and chicks at Gull Island were taken by gulls in 1998 and 1999, respectively. Kittiwakes have been indirectly (through increased predation by gulls) affected by the delayed arrival and lower abundance of capelin in recent years, which underlines the need to understand multispecies interactions when interpreting the effects of human alteration of the marine environment.
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Seamans, Mark E., and Chris Dwyer. "Annual Mortality Limit for Four Gull Species in the Atlantic Flyway." Journal of Fish and Wildlife Management 12, no. 2 (July 20, 2021): 453–63. http://dx.doi.org/10.3996/jfwm-20-088.

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Abstract We estimated the allowable annual take of great black-backed gulls Larus marinus, herring gulls L. argentatus, ring-billed gulls L. delawarensis, and laughing gulls Leucophaeus atricilla in the U.S. portion of the Atlantic Flyway to help meet human safety and resource management goals. Gulls can pose a serious threat to aviation, negatively impact other colonial-nesting migratory bird species, and conflict with other human activities. We estimated an annual take limit using a model that incorporated intrinsic population growth rate, minimum population size, and a recovery factor for each species. We estimated intrinsic population growth by combining allometric with life table approaches. We used the recovery factor to restrict the take level of the great black-backed gull beyond that of the other species because of poor data quality and concern about its population status. The herring gull was the only species with comprehensive demographic data. Population sizes used in estimating potential take limit varied greatly among the four species, but estimates of intrinsic population growth rate were similar (range 0.118 to 0.197). The annual potential take limits for the four gull species were 7,963 for herring gulls, 2,081 for great black-backed gulls, 15,039 for laughing gulls, and 14,826 for ring-billed gulls. Comparing average annual take from 2012–2019 to our modeled potential take limit, overharvest has not occurred for great black-backed and laughing gulls, occurred once every 8 y for ring-billed gulls, and occurred over half the time for herring gulls.
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Smith, Paul A., H. Grant Gilchrist, James N. M. Smith, and Erica Nol. "Annual Variation in the Benefits of a Nesting Association Between Red Phalaropes (Phalaropus Fulicarius) and Sabine's Gulls (Xema Sabini)." Auk 124, no. 1 (January 1, 2007): 276–90. http://dx.doi.org/10.1093/auk/124.1.276.

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AbstractBy nesting near aggressive birds, timid species can reap the benefits of aggressive nest defense while avoiding the costs. Red Phalaropes (Phalaropus fulicarius; hereafter “phalaropes”) typically nest in grass-sedge marshes, but nests have also been noted in rocky coastal habitats. We studied the reproductive ecology of phalaropes at East Bay, Southampton Island, Nunavut, to determine whether their use of coastal nest areas reflected a protective nesting association with an aggressive larid, the Sabine's Gull (Xema sabini; hereafter “gull”). From 2000 to 2002, we found and monitored 29 phalarope nests with gull nests nearby (≤150 m away) and 26 without gulls nearby. Coastal phalarope nests were nearer to gull nests than expected by chance. No habitat differences were detected between coastal areas with and without gull nests, but only three phalarope nests were found in coastal areas without gull nests. Thermistor probes inserted in phalarope nests revealed that incubators with gulls nearby behaved less cryptically, taking more frequent and longer incubation recesses. In human-approach experiments, phalaropes with gulls nearby flushed earlier than those without gulls. In 2000 and 2001, hatch success was 17–20% higher for phalaropes with gulls nearby, but these nests had lower success rates than those without nearby gulls in 2002. These gulls are able to defend their nests from avian predators only; in 2002, arctic foxes (Alopex lagopus) were abundant, and their primary prey, collared lemmings (Dicrostonyx torquatus), were scarce. We suggest that phalaropes select coastal areas near gulls, but that this association is beneficial to phalaropes only in years when egg predation by arctic foxes is low.Variation Annuelle des Bénéfices d'une Association pour Nicher entre Phalaropus fulicarius et Xema sabini
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Robertson, Gregory J., David Fifield, Melanie Massaro, and John W. Chardine. "Changes in nesting-habitat use of large gulls breeding in Witless Bay, Newfoundland." Canadian Journal of Zoology 79, no. 12 (December 1, 2001): 2159–67. http://dx.doi.org/10.1139/z01-180.

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We counted herring gull (Larus argentatus) and great black-backed gull (Larus marinus) nests in the Witless Bay Seabird Ecological Reserve in southeastern Newfoundland, Canada, in 1999 and 2000 and compared our results with previous nest counts from the 1970s. On Gull Island, herring gull nest numbers were 27.5% (1999) and 30.0% (2000) lower than in 1979. Similarly, on Great Island, by 2000 the numbers of herring gull nests had declined 40.8% from numbers in 1979. Counts of great black-backed gull nests were more variable, but suggest a slight or no reduction since 1979. Numbers of herring gulls nesting in rocky and puffin-slope habitats were much reduced (50–70%), while numbers nesting in meadows and forests have actually increased since the 1970s. Great black-backed gulls showed a similar change in nesting distribution. For herring gulls, these changes in nesting numbers matched differences in reproductive success previously documented in these habitats. We suggest that the decline in gull numbers and the change in breeding-habitat selection were caused by changes in the food availability for gulls. Reduced amounts of fisheries offal and the delayed arrival onshore of capelin (Mallotus villosus), an important fish prey species for gulls, have all likely led to the decline in gull reproductive output. Gulls nesting in meadows and forests may be maintaining adequate reproductive output by focusing on alternative prey, such as adult Leach's storm-petrels (Oceanodroma leucorhoa), rather than scarce refuse and fish.
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Pérez-Mellado, Valentín, Mario Garrido, Zaida Ortega, Ana Pérez-Cembranos, and Abraham Mencía. "The yellow-legged gull as a predator of lizards in Balearic Islands." Amphibia-Reptilia 35, no. 2 (2014): 207–13. http://dx.doi.org/10.1163/15685381-00002945.

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Lizards and gulls cohabit in several Mediterranean islands. The yellow-legged gull, Larus michahellis, was found to prey several vertebrate species. However, precise information about the interaction between gulls and other vertebrates, particularly with lizards is still scarce. The Balearic lizard, Podarcis lilfordi, shares several coastal islets with the yellow-legged gull. Using two different sources of information, we studied the interaction of both species in Colom Island (Menorca, Balearic Islands, Spain). We studied the diet of the yellow-legged gull and learnt that the Balearic lizard is not a common prey of the yellow-legged gull. On the other hand, we studied the potential predation pressure of gulls on lizards, using plasticine models of lizards. We did two different experiments from which we can conclude that yellow-legged gulls rarely attack lizards and, consequently, cannot be considered a major threat for this endemic lizard species, at least in the population under study. Finally, we obtained evidence that plasticine models can only be employed with caution to assess predation pressure of opportunistic scavengers, much as gulls are. The majority of marks on models were not the consequence of true attacks by gulls, but the result of ground exploratory behaviour of gulls in search of any edible matter. Therefore, contrary to popular belief, in the case of the yellow-legged gull, the proportion of marked models would be an indication of ground-based wandering activity, rather than a result of its predation pressure on lizards.
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González-Solís, Jacob, Xavier Ruiz, and Lluis Jover. "Influence of food availability on interactions between Larus cachinnans and L. audouinii." Canadian Journal of Zoology 75, no. 5 (May 1, 1997): 719–24. http://dx.doi.org/10.1139/z97-092.

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Predatory and (or) kleptoparasitic interactions are greatly facilitated in mixed-species gulleries, particularly when one of the species is larger than the others. Larus audouinii, the Audouin's gull, is a threatened species breeding in sympatry with the larger L. cachinnans, the yellow-legged gull, throughout the Mediterranean. The yellow-legged gull has often been cited as the main threat to the Audouin's gull. On the Chafarinas Islands, the second largest breeding place for Audouin's gulls in the world, both gull species depend largely on commercial fisheries for food. We analyze the influence of food availability, assessed through fishery activity, on the frequency and intensity of interaction pressure by yellow-legged gulls upon Audouin's gulls during the breeding season. We studied five different types of interaction: (1) flyovers of yellow-legged gulls; (2) ground intrusions; (3) egg predation; (4) chick predation, and (5) aerial kleptoparasitism. Moreover, intensity of interaction pressure was assessed using logistic regression analysis to build a model of the"relationship between Audouin's gulls' response to yellow-legged gull flyovers as a dependent variable and fishing fleet activity as an independent variable. All interactions except aerial kleptoparasitism were significantly more frequent during days without sardine fishery activity. However, chick predation is significantly higher only during the period when yellow-legged gull has fledglings. Overall, the results of the estimated logistic model indicate a positive association between depleted food and the response by Audouin's gulls to aerial intrusions.
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Hobson, Keith A. "Use of stable-carbon isotope analysis to estimate marine and terrestrial protein content in gull diets." Canadian Journal of Zoology 65, no. 5 (May 1, 1987): 1210–13. http://dx.doi.org/10.1139/z87-187.

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Stable-carbon isotope analyses of bone collagen of gulls (Larus spp.) were used to estimate the relative proportion of marine and terrestrial protein in the diets of gulls that are known to use both types of food sources. Mean δ13C values for Glaucous-winged Gulls (n = 23) collected at a Vancouver dump and for Western Gulls (n = 18) from Southeast Farallon Island were −15.0 ± 1.3 and −15.1 ± 0.5‰, respectively. No significant difference in δ13C values was found between adult male and female Western Gulls. Archaeological gull bones (n = 3) show a mean δ13C value of −13.6 ± 1.0‰ and support the assumed marine end point of −13.0‰. The range of terrestrial protein in the diets of coastal gulls was 0–61%. The narrow distribution of δ13C values for Western Gulls from the Southeast Farallon Island colony suggests that gull colonies may be calibrated so that changes in dependence on terrestrial protein can be monitored.
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Dissertations / Theses on the topic "Gulls"

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Veitch, Brian G. "Diet choice and reproductive success of great black-backed gulls (Larus marinus) and impacts on local breeding seabird populations /." Internet access available to MUN users only, 2003. http://collections.mun.ca/u?/theses,161494.

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Cook, Aonghais. "Landscape use by gulls (Larus spp.)." Thesis, University of Newcastle Upon Tyne, 2009. http://hdl.handle.net/10443/2037.

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In contrast to the negative impacts of landscape change on many aspects of biodiversity, scavenging bird species, like gulls (Larus spp.), have reacted positively and expanded their ranges. This in tum has brought a number of problems, including; damage to town centres, an increased risk of disease transmission to humans, domestic animals and livestock, an increased risk of collision with aircraft and a threat to vulnerable seabird populations. A great deal of money has been invested in measures to mitigate these problems. However, these have often been hampered by a failure to understand the ecology of the system concerned. This study employs a variety of statistical techniques to investigate factors related to the spatial and temporal distribution of gulls, the possible problems they may cause and the efficacy of measures to reduce the impact of these problems. Using structural equation modelling (SEM) it was possible to show that in contrast to other groups, like corvids which use landfill sites close to their roosts throughout the year, gulls rely most heavily on landfill sites as a source of food during the winter. However, analysis of the spatial distribution of winter gull roosts using negative binomial generalised linear models (GLMs) showed that only roosts of the black-headed gull (Larus 'ridibundasv were positively influenced by proximity to landfill sites. In contrast to the winter, when roosts were widely distributed, during the summer roosts had a coastal distribution. The problems posed by gulls to air safety and human health were investigated by analysing the spatial patterns of accidents and the incidence of salmonella carriage by 3 wild birds. In the first, bivariate k-means clustering revealed that strikes on Royal Air Force (RAF) aircraft by gulls were clustered within the 6 km surrounding major (>1000 individuals) gull roosts and landfill sites. These results were used to identify additional areas capable of supporting large numbers of gulls, and hence likely to represent a threat to aircraft in the future. I used survival analysis to investigate temporal and spatial patterns in wild bird salmonella. Passerines were more likely to be infected with salmonella than non-passerines and further analysis was indicative of gulls having a higher rate of salmonella infection than other non-passerines. Salmonella prevalence in wild birds was greatest during the winter and spring, and in areas with large populations of cattle. Having investigated the factors determining where gulls were and the risks they posed to aircraft safety and human health, I analyse the efficacy of a range of management techniques to control problem gull populations, using linear mixed effects models (LMEs). This revealed that techniques with occasional lethal events were the most effective. By using a range of statistical techniques, it was possible to disentangle a series of complex and often interacting relationships between gulls, the landscape and humans.
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Gamble, Jennifer R. "Suboptimal Foraging Behavior by Herring Gulls." W&M ScholarWorks, 2000. https://scholarworks.wm.edu/etd/1539626250.

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Keane, Shannon E. "Effects of Herring Gulls and Great Black-backed Gulls on Breeding Piping Plovers, South Monomoy Island, Massachusetts." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/35908.

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The large population of breeding Herring Gulls and Great Black-backed Gulls on South Monomoy Island, Cape Cod, Massachusetts has been thought to negatively affect the breeding success of the threatened Piping Plover. Following the Piping Plover Recovery Plan s call for gull colonies to be removed from Piping Plover breeding sites, in 1996, the USFWS conducted gull removal on part of South Monomoy Island. We determined relative gull abundance on South Monomoy Island from 1998-2000 by counting gulls within 100-m radius plots located on the shoreline. We quantified Piping Plover behavior and habitat use by conducting instantaneous and 5-minute behavioral observations. We quantified characteristics of Piping Plover nesting habitat by measuring characteristics along random transects. We measured gull abundance, beach width, and prey abundance, and then used logistic regression to determine what habitat characteristics influenced Piping Plover nesting area selection. We monitored Piping Plover reproductive success and population fluctuations on South Monomoy Island. Gull abundance in the gull-removal area was lower than gull abundance in the reference area throughout the Piping Plover breeding season. The difference in gull abundance between the areas did not affect Piping Plover behavior, nest success, chick survival, or productivity. We found that gull removal did not result in an increased Piping Plover population on the island. In both management areas, prenesting plovers preferred to forage in moist substrate habitats. Wide backshore and open vegetation habitats characterized nesting areas. Broods spent most of their time foraging and preferred moist substrate habitats when available. Plovers were not prevented from occupying more suitable habitat by large gulls. Fewer large gulls were observed near prenesting plovers, plover nests, and plover broods than near random plots. Fewer large gulls were observed in plover nesting areas than in unused areas when the nesting areas were defined by all area within 100-m or 500-m of a plover nest. We argue that this apparent spatial separation between Piping Plovers and large gulls is due to different habitat preferences among the species. We found that gull removal on South Monomoy Island did not result in increased Piping Plover reproductive success, and large gulls did not affect breeding Piping Plovers on South Monomoy Island from 1998-2000.
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Lamont, Christine Rae. "Sex allocation and reproductive costs in a gull with a long breeding season." Thesis, Lamont, Christine Rae (2004) Sex allocation and reproductive costs in a gull with a long breeding season. PhD thesis, Murdoch University, 2004. https://researchrepository.murdoch.edu.au/id/eprint/143/.

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The Silver Gull is a small gull (265 - 450g), which exhibits sexual dimorphism, with males larger than females. It has a protracted laying period of about 8 months over the winter on Penguin Island in Western Australia. The Silver Gull was studied on Penguin Island from 2000 to 2002. Completed clutches were removed from breeding pairs to induce repeat laying in order to determine the effect of increased reproductive effort on maternal body condition, egg production ability, offspring sex ratio and chick rearing capacity. Increased egg production had no significant effect on maternal body condition as measured by condition index, derived from mass divided by a measure of skeletal size. The seasonal period, divided into thirty-day intervals, had a significant impact on female condition index, with a decline in condition toward the end of the breeding season. While male condition also appeared to decline at the end of the season, this pattern was not significant. The initiation of laying varied between the three years of the study. The earliest occurred in 2000, which also experienced earlier rainfall than the later two years. Egg size and mass decreased throughout the breeding season although the number of eggs in a clutch did not decline. The size and mass of the eggs was significantly affected by the laying history of the parents, although this effect was dependent on the year in which the eggs were produced. The minimum interval required by Silver Gulls to replace a lost clutch is about 14 days. This interval increased from the start of the breeding season, but then declined toward the end, as summer was approaching. Laying interval increased significantly as the number of clutches produced by the parents also increased, up to 4 clutches in total. As more clutches were produced past this point, the laying interval became shorter. The probability of a replacement clutch being produced after clutch removal, declined as the clutch number increased and as the season progressed. Individuals that laid clutches with a larger mean mass were more likely to lay a replacement clutch. Increasing reproductive output caused a decline in the proportion of clutches that were replaced after clutch removal. The proportion of clutches that were replaced also varied between the years with the highest rates of replacement seen in 2000 which was also the year that experienced the earliest start in laying. The size of the original clutch in terms of its mean mass and volume was related to the size of the replacement clutch, but this relationship varied according to the timing of laying. During 2000 and 2001 male offspring predominated in the first two clutches produced by Silver Gulls. Further clutches that were produced demonstrated a sex ratio skewed toward females, the smaller sex in this species. Offspring sex ratio was close to equality in 2002 with very little effect caused by increased egg production. There was no effect of year, season or the laying history of the parents on hatching success. Growth rate in chicks was influenced by the year in which the chick hatched, the period during the season in which the chicks hatched, its sex and the laying history of the parents. The relationship between chick growth and the laying history, however, was complex with no consistent pattern emerging in terms of the performance of chicks from each treatment group. While the chicks from control groups generally grew faster than the chicks from manipulated parents, those individuals that were laid or raised by manipulated parents that had laid at least three clutches in total also performed well. Using the two main measures of reproductive success in the current study, egg production and chick rearing, those birds that were induced to lay multiple replacement clutches, were able to maintain a high level of condition and reproductive success. It is proposed that in the Silver Gull, only those individuals with a high level of condition continue to lay replacement clutches. If the female is unable to produce well provisioned eggs with a high chance of success, the breeding attempt is abandoned. Despite no loss of condition detected in female Silver Gulls with increasing clutch number, there was a significant shift in the offspring sex ratio toward females, indicating that strategies were in place to cope with the increased reproductive effort incurred as a consequence of repeat laying. Protracted laying in this species allows replacement of lost clutches only after maternal condition has been regained after laying.
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Lamont, Christine Rae. "Sex allocation and reproductive costs in a gull with a long breeding season /." Access via Murdoch University Digital Theses Project, 2004. https://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20050617.102950.

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Kim, Miran. "Eggs, incubation and hatching asynchrony in gulls." Thesis, University of Glasgow, 2008. http://theses.gla.ac.uk/526/.

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Birds can influence the embryonic development through incubation behaviour because avian embryos develop using parent’s body heat. Although previous studies assumed that incubation behaviour influences hatching patterns, few studies have studied the effect of incubation behaviour during egg-laying and early incubation on hatching patterns due to difficulties to determine onset of incubation during egg-laying. I investigated whether incubation behaviour during egg-laying and early incubation affects hatching patterns in gulls using measurements of mean nest attendance and daily change of nest attendance. Hatching patterns were influenced by incubation behaviour during egg-laying and early incubation behaviour. As parents spent more time in their nests, a brood hatched more synchronously and hatching success of the first-laid eggs increased when gulls laid relatively smaller first-laid eggs than other pairs. Within-clutch variation in eggshell colour related to daily change of incubation behaviour. This might relate to hormonal change during egg-laying. Increase of prolactin initiates incubation and accompanies decline of steroid hormones which relate to accumulation of eggshell pigments. Hatching patterns may also be influenced by accelerated development of last-laid eggs. When eggs were swapped to increase interval between eggs, last-laid eggs of herring gulls accelerated their development to catch up. Accelerated development may increase the survival of chicks from last-laid eggs by reducing the disadvantage of small size within a clutch. However, the costs of accelerated development seem to appear during the embryonic period. Hatching success was low in eggs with accelerated development, although there were no differences in growth rate and early nestling survival between accelerated and control last-laid eggs. Eggshell characteristics might be a factor affecting hatching patterns because they are related to embryonic metabolism. Hatching duration was not related to eggshell thickness and total functional area, but chicks which hatched from eggs with higher proportion of mammilllary cone contact area took longer to hatch. Chicks hatched from thicker eggshells showed longer “head plus bill” at hatching and grew faster in skeleton size after hatching. Diet during egg-laying and early incubation affected nest attendance. Females which consumed more marine food during egg formation had lower nest attendance during egg-laying and early incubation. This may relate to longer foraging time required to obtain marine food. In conclusion, this thesis suggests that parents can influence hatching patterns by altering incubation behaviour during egg-laying and early incubation and hatching patterns also may be affected by accelerated development of last-laid eggs, diet during egg-laying and early incubation and eggshell characteristics (proportion of mammillary cone contact area).
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O'Connell, Mark John. "An ecological approach to the management of gulls, in particular the lesser black-backed gull Larus Fuscus (L. 1758)." Thesis, Durham University, 1995. http://etheses.dur.ac.uk/5358/.

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A study of gull management was made at a large colony of Lesser Black-backed Gulls Ljxrus fuscus on Tambrook Fell, Lancashire. Approximately 18,000 gulls presently breed at the site, and the area utilised by the gulls extends over 6 km2 on three private estates. The main studies were conducted on the Abbeystead Estate between 1992 and 1994. The reasons for increases in the numbers of several gull species in many parts of the world during the 20th century are presented, as well as the conflicts with humans caused by these increases. The practical and moral aspects of managing gulls are evaluated, as well as the conflicts likely to result from recent increases in the urbanisation of several Larid species. The need for management strategies to incorporate up-to-date knowledge of gull demography, density dependence, breeding biology and behaviour are discussed in the light of the limited success of past attempts at managing gulls. Experiments to entirely clear specific areas of the Tambrook Fell Gullery by disturbing breeding gulls are described. The aim was to ameliorate local problems by reducing the extent of the colony using non-lethal management techniques. Disturbance was carried out in a series of 2.25ha experimental plots. Audio, visual and physical disturbance methods, presented singly or in combination, were used to investigate their ability to exclude gulls and prevent breeding. The number of gulls using the plots and the number of nests built were compared with numbers on control plots. Gulls showed habituation to all disturbance methods, although the number of gulls using a plot was reduced during disturbance and a proportion of the original number of gulls were totally excluded. Only where two disturbance methods were utilised on the same plot was breeding completely prevented. It was demonstrated that disturbance was more effective when initiated prior to the start of nest building and when conducted at the edge of the colony, and that disturbance by human presence is an effective method of preventing breeding. In the year following disturbance, only a very few gulls attempted to utilise the disturbed areas, and the need to establish a 'sink' area for birds displaced by disturbance is discussed. In two seasons, a total of 75ha were cleared of breeding gulls. This was 23% of the Abbeystead Estate and 11 % of the total gullery area. This was the first time in over thirty years of management efforts at the colony, that the extent of the gullery was successfully reduced. Models are presented to show the effects of the 1978- 1988 culls on adult survivorship and recruitment into the breeding group at Tambrook Fell. The relative effects of management strategies aimed at survivorship and productivity are discussed. A study was made to quantify the percentage of nests built by gulls at the colony that are not subsequently laid in. Behavioural differences between pairs that failed to lay eggs and pairs that successfully bred are presented. In the past, calculations of the number of breeding gulls at the colony assumed that one nest represented one pair. This was shown not to be true and a correction factor (multiplier) of 0.61 was calculated to allow counts of nests at the colony to be converted to the number of breeding pairs.
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McClellan, Rachel Katherine, and n/a. "The ecology and management of Southland's black-billed gulls." University of Otago. Department of Zoology, 2009. http://adt.otago.ac.nz./public/adt-NZDU20090827.110233.

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The black-billed gull (Larus bulleri) is a small gull that nests in dense colonies on gravel-bedded rivers in southern New Zealand. This dissertation describes research undertaken in Southland in 2004-2006 that investigates black-billed gull population decline and its causes. Historical ground counts of nests were calibrated with aerial photography of colonies and population trends analysed. The decline in breeding birds on Southland's four main rivers was equivalent to 6.0%/year (SE 1.8) or 83.6% in 30 years justifying the species' present listing as Endangered. Aerial monitoring is a poor index of the breeding population and major temporal variation was identified in counts. All re-sighted second-year birds exhibited natal dispersal and -70% left the natal catchment. Forty one percent of birds banded as adults also dispersed to other catchments. Breeding dispersal is apparently unrelated to previous breeding success and the availability of the previous year's colony site, and dispersing birds did not move as groups. Southland's black-billed gulls constitute a single inter-mixing population. Black-billed gulls selected sites on islands and banks according to availability, and selected rivers consistent with the number of gravel patches. Site vulnerability to floods varied significantly. Re-use of colony sites was positively influenced by use in previous years, the extraction of gravel, site stability and low weed cover. Widespread introduced weeds on colony sites preventing nesting and may have increased flooding risk. Colony size was related to colony area, which was related to gravel patch size. Investigation of historical changes in breeding habitat availability in Southland indicated a major reduction in gravel habitat on the Lower Oreti River between 1976 and 2002 due to river works including gravel extraction. On the Waiau River, Manapouri Dam construction in 1970 initially increased gravel areas, since reversed in the mid Waiau, and caused a 75% decline in the number of islands. Gravel patch sizes are still declining on the Lower Oreti and possibly the Mid Waiau. Hundreds of gravel patches remain on Southland rivers. Over 5000 nests in 21 colonies were monitored during incubation. Colony nest success was most influenced by colony location, averaging 90.1% (SE 2.1) on islands within rivers, and 66.8% (SE 2.2) on riverbanks, indicating that terrestrial predators exert the greatest influence on productivity. Breeding success, the mean number of fledglings produced per nest by colony, varied between 0 and 0.88 fledglings (mean 0.32, SE 0.08). Both parameters were positively related to colony size. The three smallest colonies failed to breed successfully, suggesting the presence of an Allee effect. Deterministic matrix models were used to investigate population trends using survival and productivity estimates for the closely related Kaikoura red-billed gull (L. novaehollandiae scopulinus). Adult survival, followed by breeding success and survival of first year birds, had the greatest influence on population projections. Improvements in most parameters are probably required to reverse the decline of Southland's black-billed gulls. Predation and disturbance by introduced mammals and the native black-backed gull (L. dominicanus) had the greatest impact on black-billed gull productivity. Most human disturbance is insignificant compared to predator disturbance, but illegal shooting of large numbers of adult gulls has major impacts in smaller sub-populations. Damming and excessive water abstraction reduces island habitat due to lowering of flows. Major climatic events such as droughts, and chemical ingestion through a diet dominated by agricultural invertebrates, are potential major threats about which little is known. Management actions including the collation and analysis of all unpublished black-billed gull count datasets, a thorough test of the accuracy of aerial monitoring, trialling of decoys to attract colonies to nest on islands, predator control at bank colonies, targeted weed control on high quality sites, advocacy and education and further research are recommended.
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Hart, A. D. M. "Winter territoriality of herring gulls at Walney Island, UK." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370265.

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Books on the topic "Gulls"

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Gibbons, Gail. Gulls--gulls--gulls. New York: Holiday House, 1997.

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Gibbons, Gail. Gulls--gulls--gulls. New York: Holiday House, 2001.

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Gibbons, Gail. Gulls--gulls--gulls. New York: Holiday House, 2001.

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Tom, Jackson. Gulls. Danbury, Conn: Grolier, 2008.

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Peck, George K. Gulls. Mankato, Minn: Smart Apple Media, 1998.

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Barnard, C. J., and D. B. A. Thompson. Gulls and Plovers. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4864-8.

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Calvert, Deanna. Feeding the gulls. New York: Children's Press, 2003.

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Edgcome, Anthea. Haven of gulls. Anstey: Thorpe, 1992.

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Tefono, Otila. Leai ni pato. Ueligitone, N.Z: Alagaoa o le Atamai, 1998.

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Schultz, Zella. On the wings of the wild wind. Bellingham, Wash: Center for Pacific Northwest Studies, Western Washington University, 1986.

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Book chapters on the topic "Gulls"

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Häkkinen, Henry, Silviu O. Petrovan, Nigel G. Taylor, William J. Sutherland, and Nathalie Pettorelli. "4. Gulls (Laridae)." In Seabirds in the North-East Atlantic, 90–129. Cambridge, UK: Open Book Publishers, 2023. http://dx.doi.org/10.11647/obp.0343.04.

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With key information linked to thematic maps, this section evaluates the climate change vulnerability of ten gulls (Laridae) species – European Herring Gulls, Audouin’s Gull, Caspian Gull, Lesser Black-backed Gull, Glaucous Gull, Great Black-backed Gull, Ivory Gull, Black-legged Kittiwake, Sabine’s Gull, and Yellow-legged Gull – in the North-East Atlantic. The assessments for every species cover three categories each: the exposure, or the magnitude in percentage and the characteristics of climate change; the sensitivity, or how much and by which climatic events the species are affected, depending on their biological features; the adaptive capacity, or the potential of species to respond to climate change. Assessments of local conservation actions against climate change impacts are listed here in readily consultable tables. Interventions are evaluated by evidence of effectiveness and grouped by types of impacts on gulls: increased competition due to mortality, mammal predation, exposure to pollution and heavy metals, reduced area of breeding, foraging, or prey availability, parasite load, and storms causing nest destruction, foraging difficulty, and mortality. Criteria of relevance, strength, and transparency measure the effectiveness of the actions.
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Barnard, C. J., and D. B. A. Thompson. "Gulls and Plovers." In Gulls and Plovers, 46–65. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4864-8_2.

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Barnard, C. J., and D. B. A. Thompson. "Why Feed in Flocks." In Gulls and Plovers, 1–45. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4864-8_1.

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Barnard, C. J., and D. B. A. Thompson. "Gulls and Plovers: an Overview." In Gulls and Plovers, 275–79. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4864-8_10.

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Barnard, C. J., and D. B. A. Thompson. "Choosing Where to Feed: Choice of Field." In Gulls and Plovers, 66–92. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4864-8_3.

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Barnard, C. J., and D. B. A. Thompson. "Choosing Where to Feed: Choice within Fields." In Gulls and Plovers, 93–115. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4864-8_4.

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Barnard, C. J., and D. B. A. Thompson. "Choosing What to Eat." In Gulls and Plovers, 116–42. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4864-8_5.

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Barnard, C. J., and D. B. A. Thompson. "Time Budgeting and Feeding Efficiency." In Gulls and Plovers, 143–91. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4864-8_6.

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Barnard, C. J., and D. B. A. Thompson. "Flock Dynamics: Patterns of Arrival and Departure." In Gulls and Plovers, 192–216. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4864-8_7.

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Barnard, C. J., and D. B. A. Thompson. "Kleptoparasitism: Host and Prey Selection by Gulls." In Gulls and Plovers, 217–54. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4864-8_8.

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Conference papers on the topic "Gulls"

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VEEN, J. "VOCAL COMMUNICATION IN GULLS AND TERNS." In Spring Conference '84 (Musical Acoustics and Biological Acoustics). Institute of Acoustics, 2024. http://dx.doi.org/10.25144/22606.

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Suzuki, Hirokazu, Yuichi Mizutani, Akira Narita, and Ken Yoda. "Does Aging Change Foraging Behavior of Black-Tailed Gulls?" In 2019 IEEE International Conference on Pervasive Computing and Communications Workshops (PerCom Workshops). IEEE, 2019. http://dx.doi.org/10.1109/percomw.2019.8730789.

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van der Leun, Joanna. "Gulls on the move? Synanthropic design in the Dutch Delta." In DRS2024: Boston. Design Research Society, 2024. http://dx.doi.org/10.21606/drs.2024.195.

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Harvey, Christina, Vikram B. Baliga, and Daniel J. Inman. "Control force required to morph the elbow and wrist in gulls." In AIAA Scitech 2020 Forum. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2020. http://dx.doi.org/10.2514/6.2020-1037.

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Ben-Gigirey, Begoña, María V. Mena, Christelle Mazuet, Pilar Riobó, and Francisco Rodríguez. "Paretic syndrome in gulls from southern Portugal: searching for the causative agent." In 1st International Electronic Conference on Toxins. Basel, Switzerland: MDPI, 2021. http://dx.doi.org/10.3390/iect2021-09167.

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Zhao, Yi Fan, Wei Zhang, Zhen Ting Shi, Jun Ying Jin, and Wei Hua Zhang. "Characterization of the Hydrodynamics of Fine Channel Erosion on Slopes." In 9th Annual International Workshop on Materials Science and Engineering. Switzerland: Trans Tech Publications Ltd, 2024. http://dx.doi.org/10.4028/p-nyn4eu.

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This paper reviews the results of research on the hydrodynamic characteristics of fine gully erosion, including parameters such as flow velocity, runoff depth and flow resistance. Experimental and simulation studies are carried out to address the problem of fine gully erosion in purple and loess areas, revealing the importance of fine gully erosion in hydraulic erosion. It has certain reference value for the establishment of hydrological and soil erosion modeling.
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Wells, Robert R., Carlos V. Alonso, and Andrew Simon. "Gully Study Revisited." In World Water and Environmental Resources Congress 2005. Reston, VA: American Society of Civil Engineers, 2005. http://dx.doi.org/10.1061/40792(173)186.

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Harikrishnan, N. B., and K. P. Soman. "Detecting Ransomware using GURLS." In 2018 Second International Conference on Advances in Electronics, Computers and Communications (ICAECC). IEEE, 2018. http://dx.doi.org/10.1109/icaecc.2018.8479444.

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Sanocki, Tom. "Gary the Gull." In SIGGRAPH '16: Special Interest Group on Computer Graphics and Interactive Techniques Conference. New York, NY, USA: ACM, 2016. http://dx.doi.org/10.1145/2933540.2934352.

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Edwards, Liam. "Design Challenges of the Horotiu Paa Bridge - Maximising Structural Efficiency and Economy." In IABSE Congress, Stockholm 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2016. http://dx.doi.org/10.2749/stockholm.2016.0814.

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The Horotiu Paa Bridge, also known as the Karapiro Gully Bridge is the largest weathering steel bridge in New Zealand. Construction of the bridge was recently completed in November 2015. The bridge is part of the Cambridge section of the Waikato Expressway in New Zealand. The Waikato Expressway is one of the seven state highways, named the Roads of National Significance, identified by the government as essential to New Zealand's economic prosperity. The bridge spans over the Karapiro Gully with a total length of 200m, consisting of four 50m long equal spans and is 24m wide, servicing 4 lanes of traffic.<p> This paper discusses the design development, key design aspects, innovations and technical challenges for the design of the Horotiu Paa Bridge.
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Reports on the topic "Gulls"

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Lowney, Martin S., Scott F. Beckerman, Scott C. Barras, and Thomas W. Seamans. Gulls. U.S. Department of Agriculture, Animal and Plant Health Inspection Service, May 2018. http://dx.doi.org/10.32747/2018.7208740.ws.

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Abundant gull populations in North America have led to a variety of conflicts with people. Gulls cause damage at aquaculture facilities and other properties, and often collide with aircraft. Their use of structures on and near water results in excessive amounts of bird droppings on boats and docks. Their presence near outdoor dining establishments, swimming beaches, and recreational sites can lead to negative interactions with people. Large amounts of gull fecal material pollutes water and beaches resulting in drinking water contamination and swim bans. A combination of dispersal techniques, exclusion and limited lethal control may reduce damage to an acceptable level. Gulls are classified as a migratory bird species and are protected by federal and, in most cases, state laws. In the United States, gulls may be taken only with a permit issued by the U.S. Fish and Wildlife Service. Occasionally, an additional permit is required from the state wildlife management agency.
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Wieting, Celeste, Sara Rathburn, and John Kemper. Evaluation of gully erosion for archaeological preservation in Wupatki National Monument. National Park Service, 2024. http://dx.doi.org/10.36967/2302447.

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Wupatki National Monument contains an abundance of prehistoric and historic archaeological sites that are vulnerable to gully erosion from heavy sporadic rainstorms. Increased erosional risks are predicted as more extreme weather causes frequent or intense rainfall, flooding, and gullying. At Wupatki National Monument, gullies generally form on hillslopes within volcanic-derived cinders that are ubiquitous across the landscape and are unconsolidated, non-cohesive, highly mobile, and permeable. Lithological differences between volcanic cinders and underlying sedimentary rocks, and surface runoff influence the progression of gully erosion near archaeological sites. We assessed gullies based on changes in gully morphology and categorized archaeological sites based on vulnerability from erosion and runoff processes. We found that 35 measured gullies are actively eroding, with statistically significant changes in gully depth from 2016 to 2021. Up to 0.5 m of incision was documented over a five-year period. A structure from motion analysis at the hillslope scale confirmed gully morphological changes and supports the applicability of conducting similar analyses on a larger scale. More erosion occurred in gullies with catchments predominantly covered with cinders because of cinder mobility. We noted a weak relationship between gully catchment area and gully head slope, likely related to runoff processes from outcrops of resistant sedimentary rocks forming cliffs and characteristics of cinders that maximize infiltration and transport. Based on our assessment of gully morphologic change and substrate characteristics, 22 archaeological sites along Wupatki Wash were identified as having a high vulnerability to erosion, helping monument managers to prioritize their monitoring initiatives.
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Knight, Lynn, and Suzy Hodgson. Economics of Gully Erosion Stabilization. USDA Northeast Climate Hub, July 2018. http://dx.doi.org/10.32747/2018.6893749.ch.

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Rainfall intensity is increasing in the Northeastern U.S. Stabilizing gullies is one strategy for adapting to this changing climate. This case study evaluates the costs and benefits of restoring gullies at Last Resort Farm.
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Cameron, G. D. M., and E. L. King. Seafloor-slope analysis, The Gully, Scotian Shelf, offshore eastern Canada. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2008. http://dx.doi.org/10.4095/224959.

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Cameron, G. D. M., and E. L. King. Sun-illuminated seafloor topography, The Gully, Scotian Shelf, offshore eastern Canada. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2008. http://dx.doi.org/10.4095/224960.

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Coyle, M., F. Kiss, and D. Oneschuk. Residual total magnetic field, Gull Rapids 54 D/06, Manitoba. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2004. http://dx.doi.org/10.4095/215909.

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Amos, C. L., and G. B. Fader. Natural Resource map Series of Sable Island Bank, the Gully Middle Bank, and Banquereau. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1988. http://dx.doi.org/10.4095/128160.

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Cameron, G. D. M., E. L. King, and D. C. Campbell. Surficial geology and sun-illuminated seafloor topography, The Gully, Scotian Shelf, offshore Eastern Canada. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2008. http://dx.doi.org/10.4095/224961.

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Coyle, M., F. Kiss, and D. Oneschuk. First vertical derivative of the magnetic field, Gull Rapids 54 D/06, Manitoba. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2004. http://dx.doi.org/10.4095/216029.

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Smith, Stephen. Analysis of kettle pond plant communities of Cape Cod National Seashore (1995?2020). National Park Service, 2023. http://dx.doi.org/10.36967/2300645.

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Along transects and within boxplots, several ponds have experienced significant changes in macrophyte species composition since 1995, while others have remained relatively unchanged. In 2020 new occurrences of Phragmites australis (common reed) were documented in Duck (a single plant, which was immediately removed), Gull, and Higgins ponds. Three state-listed rare species that occur in CACO kettle ponds were not found in 2020. These included Sabatia kennedyanna (Plymouth rose gentian) (found in 2016 at Great-T), Drosera filiformis (threadleaf sundew) (found in 2016 at Great-W) and Sagittaria teres (quill-leaved arrowhead), which was once abundant but has now been absent for decades. Reductions in the cover of N. odorata (white waterlily) along transects was observed in Great-T, Ryder, Higgins, and Snow ponds, although this trend was apparent in boxplots only in Herring Pond. E. acicularis (dwarf harigrass) also diminished in cover in several ponds, including along Duck, Dyer, Gull, Long, Round-E, and Slough ponds. J. militaris (bayonette rush) appears to have undergone a variety of short-term changes including reductions along transects in Great-T, Higgins, Long, and Snow ponds. Boxplots only exhibited a reduction in Higgins Pond, however. L. dortmanna (Cardinal flower) is another taxon common to most CACO ponds. Its abundance along the Gull Pond transects decreased, contrasted by an increase in Long Pond transects, and in Great-W and Round-E boxplots. The proliferation of Utricularia spp. in Great-T Pond is one of the most conspicuous changes that has occurred over the last decade. The plant community shifts reported here are likely the result of both short-term (e.g., trampling, geese grazing, extreme drought or high water, etc.) and long-term (e.g., climate warming, diminishing acidity, increasing alkalinity). That said, many of the statistically significant increases or decreases in cover were restricted to just one or two transects, and sometimes the changes in individual taxa contrasted each other among the different transects. One-dimensional line-intercept transects are likely detecting changes that are not real on any meaningful spatial scale. On the other hand, the number of boxplot sites should be increased to obtain much better spatial resolution. Accordingly, we propose increasing the number of box plot sites in each pond from five to ten for all future monitoring.
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