Individual study: Post-release survival and breeding productivity of rock ptarmigan Lagopus muta reintroduced to Agattu Island, Aleutian Archipelago, Alaska, USA
Kaler R.S.A., Ebbert S.E., Braun C.E. & Sandercock B.K. (2010) Demography of a reintroduced population of Evermann's rock ptarmigan in the Aleutian Islands. Wilson Journal of Ornithology, 122, 1-14
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A replicated study reviewing a translocation programme in 2003-6 in the western Aleutian Islands, Alaska, USA (Kaler et al. 2010), found that 15% of 13 newly translocated female Evermann’s rock ptarmigans Lagopus muta evermanni died within two weeks of release, but that confirmed overwinter mortality was similar for translocated and resident females (30% of ten translocated females known to have died vs. 33% of six resident females). All surviving females nested, laying on average eight days later than 16 resident females (16th June vs. 8th June) and producing significantly fewer eggs (average of 6.8 eggs/clutch vs. 8.3 eggs/clutch). Egg size and nest survival were similar between resident and translocated females, whilst brood survival was higher for translocated females (85% for eight translocated females vs. 25% for 13 residents). Fecundity was also higher for translocated females, but this difference was not significant (0.9 female fledglings/translocated female vs. 0.3 male fledglings/resident female). In total, 75 birds were caught on Attu Island, held for up to 48 hours and fed on melon whilst being moved and then released on Agattu Island immediately upon arrival. One male bird died during transit.