Gyrfalcon Nest Site Fidelity, Breeding Dispersal, and Natal Dispersal in Alaska Using Non-Invasive Genetic Sampling.

Abstract

We used molted feathers naturally shed from adult Gyrfalcons as non-invasive genetic samples following methods similar to those in Sonsthagen et al. (2004), Waits and Paetkau (2005), and Rudnick et al. (2005, 2008. We collected samples in breeding territories to document nest site fidelity, breeding dispersal, and natal dispersal at three study areas located 100-350 km apart on the Yukon Delta National Wildlife Refuge (Figure 1, Askinuks, Volcanoes, and Kilbucks), Alaska, from [2003][2004][2005][2006][2007]. We defined breeding dispersal as movement among nest sites and natal dispersal as movement from a bird's natal nest site to its nest site of first breeding. The number of feathers collected per individual per site ranged from 0-34 feathers (Figure 2). Gyrfalcons were highly faithful to study areas and territories; we documented no breeding dispersals among study areas and only one dispersal event between territories. Gyrfalcons exhibited low nest site fidelity; only 22% of birds returned to the same nest site the following year. The remaining 78% moved 50-3,400 m from the previous alternate nest site. Dispersal distance averaged 750 ± 870 m (SD), and was similar between sexes (females 754 ± 950 m (SD), n = 19; males 745 ± 740 m (SD), n = 10). Mean annual turnover at the Volcanoes study area was 20%. We detected three natal dispersal events ranging from 0-254 km representing 2.5% recruitment of the 121 sampled nestlings.

Distribution and movements of Alaska-breeding Steller's Eiders in the nonbreeding period

“…Interchange of breeding areas may not apply to females, however, since female breeding site fidelity is common in eiders Powell 2006, Petersen 2009), including the 1 female in this study (ID 9918) that was tracked long enough to document her apparent return to the breeding area in Alaska. Additional studies are needed to acquire a better understanding of breeding site fidelity of Steller's Eiders, including noninvasive DNA approaches (Rudnick et al 2009, Booms et al 2011) that have the potential to yield larger sample sizes at lower cost and with less risk to study subjects than telemetry.…”

Cross-species Amplification of Microsatellite Markers in the Great Horned Owl <i>Bubo virginianus</i>, Short-eared Owl <i>Asio flammeus</i> and Snowy Owl <i>B. scandiacus</i> for Use in Population Genetics, Individual Identification and Parentage Studies

“…Similarly, the use of microsatellite loci in studies of reproductive behavior in birds often reveals a higher incidence of extra-pair paternity than previously thought based on behavioral observation alone (Griffith et al 2002, Casey et al 2011. Microsatellite analyses can also facilitate individual identification in situations where bird banding may be unfeasible, such as genetic-tagging studies to investigate nest-site fidelity in raptors (Booms et al 2011). However, the identification of microsatellite markers is labor-intensive and costly, and within the Strigiformes microsatellite markers are currently available for only nine species (GenBank search, 22 April, 2012).…”