Abstract:

Studies on the breeding biology of birds provide relevant information about their life history and allow the understanding of the ecological aspects that can influence their breeding success and population trends. Between October and February 2017 to 2020, we monitored nests of South American Snipe (Gallinago paraguaiae) in a grassland under low density livestock pressure located in the Flooding Pampa, in north-eastern Buenos Aires Province, Argentina. We searched for nests by rope-dragging and monitored them regularly until either they hatched or failed. We measured each nest and its surrounding vegetation (including lateral and vertical visual obstruction readings), and distances to grassland edges. We analyzed nest-site preferences comparing nests vegetation to vegetation at random points, and estimated the apparent nest success and daily nest survival rate (DSR) of the species. We found 15 nests which had a mean clutch size of 2.8 eggs. Nests were built in ~60-centimeter-high grass clumps, and had more horizontal visual obstruction than random points. Only three nests were successful (apparent nest success = 20%) and predation was the main cause of nest failure. Nest DSR was 0.879, with a cumulative probability of survival of 8.6% during the incubation period, which is low compared to similar species. We emphasize the need to study nest predators in the region and to continue studying avian populations breeding in these habitats, in order to shed light on the effect of habitat alteration on the population dynamics of these birds