Academic literature on the topic 'Migratory habit'

Abstract We investigated whether wing morphology differed between the sedentary House Finches (Carpodacus mexicanus) of western North America and the introduced population of eastern North America, as the latter has developed migratory behavior since its inception. Wing morphology differed between eastern and western House Finches. Eastern House Finches had shorter proximal primaries and a longer outer primary, perhaps reflecting a thinner and more pointed wing, although no disparity in wing length was detected. Since we interpret these differences in wing shape as modifications for flight capability, we believe that initial evidence for morphological divergence relative to migratory habit between eastern and western House Finches has been established here. Confirmatory studies to determine if wing morphology varies according to the gradient in expression of migratory behavior throughout the range of eastern House Finches are now warranted. La Forma Alar en Carpodacus mexicanus Difiere en Relación a los Hábitos Migratorios entre el Este y Oeste de Norte América Resumen. Investigamos si la morfología del ala difería entre individuos sedentarios de Carpodacus mexicanus del oeste de Norte América y la población introducida en el este de Norte América, la cual ha desarrollado un comportamiento migratorio desde su inserción. La morfología del ala difirió entre las poblaciones de C. mexicanus del este y del oeste. Los individuos del este tuvieron primarias proximales más cortas y primarias externas más largas, lo que quizás refleja un ala más fina y más puntiaguda, aunque no se detectó una diferencia en el largo del ala. Ya que interpretamos estas diferencias en la forma del ala como modificaciones para la capacidad del vuelo, creemos que se ha establecido una evidencia inicial de divergencia morfológica en relación con el hábito migratorio entre las poblaciones de C. mexicanus del este y del oeste de Norte América. Actualmente, son necesarios estudios que confirmen y determinen si la morfología del ala varía de acuerdo al gradiente de expresión del comportamiento migratorio a través del rango de distribución de la población de C. mexicanus del este.

Integrated studies of the geographical, ecological, and historical factors that shape intraspecific phenotypic and genetic variation can help us to decipher the processes leading to geographic patterns of population divergence and speciation. We quantify and compare morphological and genetic variation in the Loggerhead Shrike (Lanius ludovicianus Linnaeus, 1766), a broadly distributed passerine in North America with both migratory and non-migratory populations that occupy a diversity of habitats and topographies. The geographic distributions and patterns of differentiation among subspecies suggest that migration has strongly impacted population divergence, including the habit of migrating itself, but also dispersal. Patterns of mitochondrial and nuclear genetic differentiation can be attributed to female-biased dispersal and to increased dispersal rates and distances in migratory populations. Weak phenotypic differentiation among migratory versus migratory and non-migratory populations suggest that migration may more strongly affect morphology than adaptation to local habitats. Our results generally support previous subspecific designations with two notable exceptions. We found little genetic differentiation between two subspecies (Lanius ludovicianus gambeli Ridgway, 1887 and Lanius ludovicianus mexicanus C.L. Brehm, 1854), but identify a new, distinct subspecies, which we refer to as Lanius ludovicianus centralis ssp. nov.

Abstract In order to compare the two species’ flight performance over the exposed and windy Falsterbo Peninsula, where thermal conditions seldomly are very favorable, we used tracking radar to study flight parameters of sparrowhawks Accipiter ni-sus and common buzzards Buteo buteo during autumn migration. The results showed a clear difference between sparrowhawks and common buzzards in their flight altitudes and speeds, and in the wind conditions they encountered. Common buzzards had higher flight altitudes and were more selective of wind. Flight altitude was negatively related to the wind speed, which was most pronounced for common buzzards. Sparrowhawks had higher mean air- and cross-country speeds than common buzzards. Airspeed was negatively related, whereas ground and cross-country speeds were positively related to the tailwind component for both raptors. The differences between sparrowhawks and buzzards could to a large degree be explained by a larger dependence on thermal soaring among the common buzzards; a strategy associated with selectivity for favourable thermal and wind conditions during migratory flight. An additional important explanation for the interspecific differences was the habit of the sparrowhawks to combine migratory flight with hunting for prey, which makes it prone to fly at lower altitudes and use flapping flight to a much larger degree than common buzzards which do not forage during their migratory passage of the Falsterbo Peninsula.

Abstract We assessed the effects of range disjunction, migratory habit, coloniality, and habitat structure on the genetic differentiation of North American Burrowing Owl (Athene cunicularia) populations. Burrowing Owls in North America comprise two forms or subspecies: A. c. floridana in Florida, separated by ∼1,500 km from the western form, A. c. hypugaea, which ranges from Texas to California and north to southern Canada. Burrowing Owls tend to be loosely colonial, and both the Florida populations and southerly populations of A. c. hypugaea from California to Texas are nonmigratory. To assess genetic structure, we examined 201 individuals from nine western and six Florida populations at seven highly variable microsatellite DNA loci. Mean gene diversity (Hexp) was higher in the west than in Florida (0.539 and 0.341, respectively; P < 0.05). Populations within subspecies were essentially panmictic (A. c. floridana: θ = 0.038, ρ = 0.014; A. c. hypugaea: θ = 0.014, ρ = 0.009) and even genetic differentiation across subspecies was modest (θ = 0.051, ρ = 0.014). Nevertheless, the western and Florida forms were easily distinguished by any of several criteria, such as allelic absences in Florida, assignment tests, and well-supported branches on the inferred phylogenetic tree. Genetic differentiation was at least twice as great in resident Florida (θ = 0.038) and California (θ = 0.021) populations as in migratory western populations (θ = 0.012), though 95% confidence intervals of theta estimates overlapped. We found no evidence of a genetic bottleneck that would result in evolutionary disequilibrium within subspecies. In the west, high observed heterozygosity values and evidence of gene flow suggest that population declines and patchy habitat, which currently imperil this species throughout much of its range, have not led to inbreeding or biologically meaningful genetic differentiation among the sampled populations.

Orientador : Paulo Sergio Oliveira<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia<br>Made available in DSpace on 2018-07-18T21:44:50Z (GMT). No. of bitstreams: 1 Leal_InaraRoberta_M.pdf: 4456041 bytes, checksum: 24cf19f7608278185a800b5b58156d2f (MD5) Previous issue date: 1994<br>Resumo: Este estudo investigou a predação em grupo e o hábito migratório da formiga neotropical Pachycondyla marginata. O trabalho de campo foi realizado em floresta semidecidua, na Reserva Municipal de Santa Genebra, Campinas, SP. Um total de 202 incurses em grupo a cupinzeiros foi observado de fevereiro de 1991 a setembro de 1993. Pachycondyla marginata predou exclusivamente cupins da espécie Neocapritermes opacus (Termitidae). As incursões ocorreram de dia e à noite, numa freqüência aproximada de uma vez a cada duas semanas, podendo durar de duas a mais de 24 horas. As colônias the P. marginata tiveram de 500 a 1500 operárias, 20% das quais estiveram envolvidas na caça. A atividade de caça na estação chuvosa foi mais intensa durante a noite. Por outro lado, o pico desta atividade na estações seca ocorreu por volta das 16:00 h. As formigas capturaram cupins operários e soldados, numa proporção média de 13:1. A distância entre o ninho de P. marginata e o cupinzeiro atacadci variou de 0~12 a 38 m e foi maior na estação seca. A remoção de partículas de solo do interior do ninho foi freqüentemente observada nas colônias de P. marginata. Esta atividade foi constante ao longo do dia na estação chuvosa, mas apresentou uma pico em torno das 16:00 h na estações seca. A porcentagem de colonias engajadas na caça ao longo do ano Ifoi mais alta na estação seca. A limpeza dos ninhos, entretanto, foi mais intensa na estações chuvosa. Migrações<br>Abstract: This study investigates the group-raiding behavior and migratory habit of the neotropical ant Pachycondyla marginata. Field work was carried out in the semideciduous forest of the Reserva Municipal de Santa Genebra, Campinas, SP. A total of 202 group-raid of termite nests was observed from February 1991 to September 1993. Pachycondyla marginata preyed exclusively on the termite Neocapritermes opacus (Termitidae). Raids on termite nests can occur both by day and by night, approximately every two weeks, lasting two ta 24 hours. Colonies of P. marginata contained 500 ta 1500 workers, 20% whom were engaged in hunting activity. In the rainy season, hunting activity was more intense during the night. On the other hand, the peak of hunting activity in the dry season was around 16:00 h. Worker and soldier termites were captured by the ants in an approximate proportion of 13:1. The distance between a colony of P. marginata and a target termite nest varied from 0.12 to 38 m. The removal of soil particles from the interior of the nest was frequently observed in colonies of P. marginata. This activity was constant throughout the day in the rainy season, being more frequent at 16:00 h during the dry season. The proportion of colonies engaged in hunting activity was higher during the dry season. Cleaning activity, however, was more frequent in the rainy season. Migration by colonies of P. marginata was recorded on occasions; nest relocations lasted 1-2 days and covered distances Df 2 to 97 m. Colonies relocated their nests to greater distances during the dry season. The approximate residence time Df ant colonies at a given location was 150 days. Some colonies Df P. marginata had more than one dealated 1emale and colony 1ission could occur when these reached maturity. Success Df colony foundation was approximately 43%. Group-raiding and nomadism are considered diagnostic behavioral patterns Df army-ants. The predatory and migratory behaviors Df P. marginata probably represent an early stage in the evolution Df the true army-ant habito<br>Mestrado<br>Ecologia<br>Mestre em Ciências Biológicas

This chapter draws on an array of sources including twentieth century scientific studies to offer insight into the habits and migratory patterns of sea turtles. As a result, the chapter discusses basic sea turtle biology differentiating the distinctive features of green and hawksbill turtles. It then explains how the two turtle varieties became global commodities for niche luxury markets. The chapter explains how indigenous and early New World newcomers—both European and non-European—came to adapt and learn how to hunt turtles in the Caribbean. It also traces the development of turtle hunting in the Cayman Islands. The chapter argues that turtles played a pivotal role in shaping these small islands and coastal societies as much as sugar or banana commodities did in other parts of the Caribbean.