Rates Of Philopatry Research Articles

High philopatry rates of Yellow-legged Gulls in the southeastern part of the Bay of Biscay

BackgroundPhilopatry rate is one of the main factors shaping population dynamics in colonial seabirds. Low rates of philopatry are linked to populations with high dispersal, while high rates are linked to populations with a very high spatial structure pattern (i.e., metapopulations). The Cantabrian Yellow-legged Gull (Larus michahellis) population is considered to be resident, with relatively low dispersal rates. Precise estimations of its philopatry rates are however still lacking. Here, we aimed to estimate philopatry rates in the main Yellow-legged Gull colonies of the province of Gipuzkoa, in the southeastern part of the Bay of Biscay.MethodsWe analysed 734 resightings, during the breeding season at the colonies of Getaria, Santa Clara and Ulia, relative to a total of 3245 individuals ringed at birth in these same colonies during a period of 13 years. These data were analysed using Multi-State Recapture models in MARK.ResultsAfter controlling survival and resighting probability, the average dispersal rate among colonies was 4% (± SD = 2%) when individuals are immature, decreasing to 1 ± 1%) for adult breeding gulls (i.e., philopatry rate was 99%). Annual survival rates were assessed to be 0.27 ± 0.02 for birds in their first year of life and 0.87 ± 0.01 for older individuals. The probability of observing immature birds in the colonies was 0.08 ± 0.01, as compared to 0.21 ± 0.02 in adult birds.ConclusionsWe obtained evidence of extremely high local philopatry rates, clearly within the upper limit found in gulls. A high philopatry favour a speciation in these species who are vulnerable to obtain the main food source (landfills and fishing discard) which are transforming under new ecological process.

Natal Philopatry and Juvenile Survival in Swainson's Warblers (Limnothlypis swainsonii)

ABSTRACT.— Understanding natal dispersal and rates of philopatry can help provide minimum estimates of juvenile survival, a vital demographic parameter for which little information is available. However, despite the large number of hatch-year migratory birds banded every year at their natal sites, few are resighted or recaptured. Here, we report on the return of 22 Swainson's Warblers (Limnothlypis swainsonii) banded as nestlings or fledglings between 1997–2008 at breeding sites in Arkansas, North Carolina, and South Carolina, USA. Of 284 nestling Swainson's Warblers banded, we found 13 (4.6%) exhibiting natal philopatry. Of 95 fledglings banded, we detected 9 (9.5%) in later years. The median distance moved from the original capture to an encounter location the subsequent breeding season for all second-year birds we detected was 1.5 km (range = 54 m to 15.4 km). The mark-recapture estimate for first-year apparent survival was 0.119 (SE = 0.032). Estimated recapture probability was between 0.55 and 0.65. ...

The Migration of the Lesser Kestrel Falco naumanni in Eastern Europe - A Ringing Recovery and Direct Observation Approach

Abstract We examined ringing recovery data of the Lesser Kestrel Falco naumanni in order to analyse its migration patterns and philopatry rates in Eastern Europe. In addition, we extracted counts of migrating birds from online databases and studied the use of the flyway as well as the phenology of both spring and autumn migrations through Greece. Birds appeared to migrate in the same mean direction in spring and autumn through the Italian and Balkan Peninsulas. During spring, movements took place on a broad front from March until mid- May with a peak in mid-April; in autumn, birds migrated through Greece on a narrower front from early August to early October, with most of individuals passing through Greece in mid-September. Finally, philopatry rates were higher for adults, while juvenile birds dispersed more often and at longer distances, up to 974 km away. Our results on migration patterns generally agree with those in other studies, but we found some evidence of long-distance premigratory movements towards mainland Greece that could also shape the narrower front migration in autumn. In addition, long distance dispersal movements of juveniles in southeastern Europe, where Lesser Kestrel populations show a fragmented distribution, could facilitate gene flow between populations, thus avoiding the negative effects of mating with genetically similar individuals.

Social and Genetic Mating System of the American Golden-Plover

Shorebirds are exceptionally diverse in their social mating systems, and genetic analyses of a few species have revealed further variation in genetic mating systems. The ecological and evolutionary causes of this variation are largely unknown. We studied the mating system of American Golden-Plovers (Pluvialis dominica) at Barrow, Alaska, between 2004 and 2009. In this arctic population, birds bred in socially monogamous pairs, as has been seen in other populations, yet rates of philopatry and mate fidelity were low. We used microsatellite DNA markers to analyze parentage and found that most offspring originated from monogamous matings, but 8% of 131 offspring and 16% of 37 nests were the result of nonmonogamous matings. One nest was ambiguous; it was either a full clutch sired through extra-pair copulation or represented an instance of social polygyny. Despite wide variation in synchrony of breeding and density of nesting both within and among breeding seasons, these ecological variables were unrelated to mating patterns. We speculate that the low rate of pair fidelity and the high rate of extrapair paternity are linked, because the lack of familiarity between partners reduces benefits of monogamy. Further study of breeding behavior and rates of philopatry are needed to understand why, among socially monogamous shorebirds, the American Golden-Plover has high rates of extra-pair paternity.

Natal Philopatry and Apparent Survival of Juvenile Semipalmated Plovers

Natal philopatry is rare in long-distance migrant shorebirds and requires long-term population studies to detect. We report on the rate of natal philopatry from a 18-year study of Semipalmated Plovers (Charadrius semipalmatus) marked as hatchlings to an arctic breeding site near Churchill, Manitoba. About 2% (27/1271) of banded hatchlings returned to the Churchill area to breed. There was no male/female bias in rates of philopatry: 17 male and 10 female hatchlings recruited into the local breeding population. The annual rate of recruitment of hatchlings varied between 0 and 10.7%. Age of first encounter on breeding areas ranged from 1 to 8 years (median age 4) suggesting either unusually delayed age at first breeding, or low detection rates for philopatric hatchlings. The maximum age of a recruited (known-age) hatchling was 9 years. Natal dispersal distances did not differ between males and females, and averaged 5 km between hatching and breeding locations. We used a time-since-marking mark-recapture model to calculate apparent survival of hatchlings. Apparent survival in the interval after first capture was φ1 = 0.0475 (95% CI: 0.030–0.075), whereas apparent survival (φ2 ) of birds during subsequent intervals was 0.866 (95% CI: 0.764–0.927). Low rates of natal philopatry suggest little advantage to site familiarity for juveniles, and agree with theoretical predictions for migratory species with widespread habitat availability.

Natal Philopatry, Competition for Resources, and Inbreeding Avoidance in Townsend's Voles (Microtus Townsendii)

Individuals may leave their birthsite before reproducing or they may postpone reproduction because they are at risk of engaging in inbred matings with their close relatives or because they are exposed to severe competition for resources or for mates. I studied whether avoidance of inbreeding and intrasexual competition determine the seasonal changes in the rate of philopatry and the fate of individual Townsend's voles (Microtus townsendii). By marking most nestlings before weaning, I knew which recruits were related to one another and to which adult female. There was a pronounced sexual bias in the tendency to remain close to the birth site: 9% of all juvenile males 33% of all juvenile females entered the breeding population on their natal grid. Males settled farther from their birth site than females did. The proportion of males and females reproducing on their natal grid changed markedly over the breeding season. More males and females reproduced if they were born at the beginning of the breeding season or when breeding activity was depressed by botfly infestation. Seasonal changes in female philopatry were consistent with the hypothesis that females disperse in response to competition for resources with breeding females. Females born at high adult female density were less likely to be recruited than those born at other times. They also dispersed farther at low than at high density, probably in response to habitat saturation. Avoidance of extreme inbreeding influenced the dispersal tendency of maturing males. Males were less likely to join the breeding population if their mother or a littermate sister was present in their home range when they matured than if they had no female close relatives in their home range. Males with their mother alive at sexual maturation settled farther than males whose mother had disappeared by that time. I concluded that inbreeding avoidance influenced natal philopatry in males and that competition for resources influenced natal philopatry in females.