Winter ground segregation between two neighboring breeding penguins

BARRIONUEVO MELINA; ANNICK MORGENTHALER; NAHUEL MARCHISIO; ANA MILLONES; ESTEBAN FRERE

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Congreso; World Seabird Conference; 2021

Knowing dispersion of seabirds during migration may provide predictable foraging areas, potential overlap with human activities and target conservation zones. Penguins spend half of the year dispersing at sea during the non-reproductive stage. The aim of this study was to analyze habitat use of Rockhoppers penguins -RH- (Eudyptes chrisocome chrisocome) & Magellanic penguin -MP- (Spheniscus magellanicus) during the winter period. We study through geolocators (MK3 & MK4) the migration of 10 RH breeding at Isla Pingüino (47°54?S; 65°43?W) and 20 MP breeding at Isla Quiroga (47°45?S, 65°53°W), Argentina during 2019. We found that RH migrated north reaching north of Uruguay?s coast (32°30?), but males went also southern than females, reaching Antarctic Ocean and spending 33% of the time southern to their breeding colony (vs. 7% of females). Males dispersed more than females: latitudinal length (distance between northmost and southmost point) was 2250 km for females and 3250 km for males, and 50% Kernel density contour for males was ~threefold larger than that of females. Females' habitat is mostly included in males? habitat (between 30% and 100%). Males migrate more offshore (~190 km vs. 145 km) and spent more time in colder waters than females. Migration of MP was previously described and was similar to RH females, but very different from RH males. Latitudinal length of PM was of 2100 km and used warmer waters than RH. Fifty-percent Kernel overlap between RH and MP were around 40-60% during April-May to 30% in June-July and no-overlap in August, females RH were exclusively responsible for these shared-areas because males RH were south and offshore, even beyond the continental shelf. Different diets and breeding schedule might be responsible for the segregation. This study shows sexual segregation in RH at a latitudinal and longitudinal levels, and an overlap between MP and females RH habitats.