The annual survival of migratory Nearctic shorebirds depends on numerous factors which they encounter during their annual cycle. However, a significant knowledge gap exists concerning the winter survival for many species that winter in South America. The semipalmated sandpiper (Calidris pusilla) is a neotropical migratory shorebird that has been in steady decline for the last 40 years and is now listed as a near threatened species by the International Union for Conservation of Nature (IUCN). Aerial survey data from South America has suggested that since the 1980s, up to an 80% decrease has occurred to the wintering semipalmated sandpiper population in the Guianas, which is hemispherical important wintering habitat for shorebirds. Observed habitat loss and change of coastal habitat is a potential explanation for population loss. Additionally, illegal hunting of shorebirds is prevalent and may have a significant role in the winter survival of many shorebird species. In this study, we are using automated tracking systems (Motus towers) and uniquely coded radio transmitters (nanotags) to measure the winter survival of semipalmated sandpipers in Suriname and French Guiana. Our objective is to understand how anthropogenic and environmental variables most affect the winter survival of semipalmated sandpipers.
Results/Conclusions
During the winter of 2016 we deployed nanotags (n=129) at three sites in Suriname and during the winter of 2017 we deployed nanotags (n=109) at two sites in Suriname and French Guiana. We recovered the detections from the 2016 nanotags and found 99 individuals (77%) were detected at least once. The number of days for detections at the three sites were 41 days, 71 days and 88 days, which suggests differences in survival rates among sites. We also found that individuals (n=12) were detected at sites other than the capture location, suggesting that significant movement is occurring during the nonbreeding season. This is the first study to investigate the winter survival for shorebirds in South America using nanotags and the first study to address the winter survival of semipalmated sandpipers. The extent of how hunting pressure affects shorebird population fitness is not fully understood, so this research is a necessary step for conservation efforts to protect this species and other wildlife in coastal Guiana. These findings will provide necessary data to fill in the gaps of knowledge for the annual cycle of semipalmated sandpipers.