Consistent apparent adult survival and nest-site fidelity of Whimbrel (Numenius phaeopus) near Churchill, Manitoba, Canada over a 40-year period

Reliable estimates of adult survival for many shorebird species are lacking. We used Cormack-Jolly-Seber (CJS) methods to provide an estimate of apparent, or local, survival (φ) of a population of Whimbrels, Numenius phaeopus, breeding in the subarctic Churchill, Manitoba region. We used data collected in two time periods: 1973–1976 and 2010–2014. We also quantified nest-site fidelity in 2010–2014 to provide context to our apparent survival estimates because mark-recapture analyses cannot distinguish between mortality and permanent emigration. The most parsimonious CJS model did not include effects of sex or time on apparent adult survival in either period (φ = 0.76 ± 0.13 SE; φ = 0.75 ± 0.04 SE, 1973 – 1976 and 2010 – 2014, respectively). Additionally, observations of marked Whimbrels between 2010 and 2019 (n = 124) showed that 61 of the 105 marked individuals (58.1%) were resighted. These estimates of return rates are, as expected, much lower than estimates of apparent survival. The m..., ,