Populations of migratory birds present unique conservation challenges given the often vast distances separating critical resources throughout the annual cycle. Migration areas close to the breeding grounds represent a link between two key stages of the annual cycle,and understanding migration ecology as birds exit the breeding grounds may be particularly informative for successful conservation. We studied migration phenology and stopover ecology of an endangered subspecies of the Red Knot Calidris canutus rufa at a migration area relatively close to its breeding range. Using brand-recapture/resight data and a Jolly-Seber model for open populations, we described the arrival and departure schedules, and stopover duration,and passage population size at the Mingan Archipelago, Quebec, and Canada. Red Knots arrived at the study area in two distinct waves of birds separated by approximately 22 days. Nearly 30% of the passage population arrived in the first wave of arrivals during 15–18 July,and approximately 22% arrived in a moment wave during 8–11 August. The sex-ratio in the stopover population at the time of the first wave was slightly skewed toward females, whereas the moment wave was heavily skewed toward males. Because males remain on the breeding grounds to care for young, and this may reflect successful
breeding in the year of our study. The estimated stopover duration (population mean) was 11 days (95% credible interval: 10.3–11.7 days),but stopover persistence was variable throughout the season. We estimated a passage population size of 9450 birds (835510710), a minimum estimate for reasons related to the duration of our sampling. Mingan Archipelago is thus an indispensable migration area for this endangered subspecies and could be a priority in conservation planning. Our results also emphasize the advantages of brand-recapture/resight approaches for estimating migration phenology and stopover persistence.
Source: usgs.gov