Seasonal demographic patterns and habitat utilization of Chloephaga picta in the Sarmiento Valley, Chubut

The present work was carried out during the winter (WS) and reproductive (RS) seasons from 2014 to 2017 in the Sarmiento Valley (45° 36’S, 69°04’W). The purpose of this research was to study seasonal demographic patterns and habitat utilization by the Upland Geese. The maximum number of specimens was estimated at 14,000 and 8,500 for WS and RS, respectively. In addition, during WS both mean numbers of individuals (429 vs 130) and flocks (63 vs 35) per transect and the proportion of barred males (8.4% vs 0.3%) was significantly higher than during RS. On the other hand, the number of flocks composed of two specimens (78% vs 48%) was significantly higher during RS. In an environment that was comparatively not very variable between seasons, the Upland Geese used in greater proportion pasture implanted habitats with the presence of domestic cattle during the WS in relation to RS. In contrast, they were associated more with high vegetation (> 20 cm) and water bodies during RS. These results would indicate that the Upland Geese adopt the expected theoretical patterns to protect their clutches (RS) and maximize the energy gain (WS).