We examined variation in persistence rates of waterfowl carcasses placed along a series of transects in tundra habitats in western Alaska. This study was designed to assess the effects of existing tower structures and was replicated with separate trials in winter, summer and fall as both the resident avian population and the suite of potential scavengers varied seasonally. Carcass persistence rates were uniformly low, with <50% of carcasses persisting for more than a day on average. Persistence rate varied by carcass age, carcass size, among transects and was lowest in the fall and highest in the summer. We found little support for models where persistence varied in relation to the presence of tower structures. We interpret this as evidence that scavengers were not habituated to searching for carcasses near these structures. Our data demonstrate that only a small fraction of bird carcasses are likely to persist between searches, and if not appropriately accounted for, scavenging bias could significantly influence bird mortality estimates. The variation that we documented suggests that persistence rates should not be extrapolated among tower locations or across time periods as the variation in carcass persistence will result in biased estimates of total bird strike mortality.

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The Holarctic distribution of Babesia microti within small rodents implies an ancient association. A seminal report of piroplasms in Alaskan voles suggested to us the possibility that B. microti entered North America within Eurasian microtine rodents dispersing through Beringian corridors. To test this hypothesis, we analyzed samples from Alaskan rodents by polymerase chain reaction for evidence of infection with B. microti; one-third of the rodents were found to be infected. Sequence analysis of the 18S rDNA gene demonstrates that Alaskan B. microti comprises a clade that infects microtines in several sites across North America and is distinct from a clade that is zoonotic.

Restoration or establishment of colonies using translocation and hand-rearing can be an effective tool for conserving birds. However, well-designed post-release evaluation studies for long-lived species are rarely implemented. We investigated the attendance and breeding attempts of hand-reared short-tailed albatross (STAL) Phoebastria albatrus chicks (n = 69) translocated to a historic breeding island in the Ogasawara Islands, 350 km from the source colony, for 8 consecutive years after the first translocation. Thirty-nine percent of hand-reared birds (n = 27) returned to the translocation site at least once per breeding season, of which 67% (n = 18) also visited the natal island. The number of hand-reared birds returning each year was lower at the translocation site (mean: 0.3-2.3 birds per day) versus the natal island (0.4-3.5 birds per day). The first breeding attempt occurred 5 years after the first translocation. Three pairs (producing three chicks) recruited to the translocation site or neighboring islands and five pairs (producing nine chicks) recruited to the natal island by 8 years after the first translocation. Every hand-reared bird that raised a chick paired with a naturally reared bird. At the translocation site and neighboring islands, two hand-reared birds paired with a mate from the natal island and a breeding colony 1850 km away, respectively, while the parents of the third chick were unknown. Their breeding at the translocation region was observed among conspecific social attractants (decoys, audio playback; one pair) or congeners (two pairs). Our preliminary results suggest that even though more translocated and hand-reared albatrosses visited and recruited to their natal island compared to the translocation site, the early re-establishment of breeding by short-tailed albatrosses in the Ogasawara Islands 80 years after extirpation would not have occurred without the initial translocation effort. Further study is needed, however, to fully understand formation of breeding colonies beyond conspecific attraction and philopatry.