WATERBIRD OCCURRENCE AND ABUNDANCE IN THE STROBEL LAKE PLATEAU, PATAGONIA, ARGENTINA

LANCELOTTI, J.L.; POZZI, L.; MARQUEZ, F.; YORIO, P.; PASCUAL, M.A.

El Hornero

Aves Argentinas/Asociación Ornitológica del Plata

Año: 2009

0073-3407

25 The Lake Strobel Meseta is a conspicuous and representative26 basaltic “meseta” in the Patagonian steppe, Argentina. This27 “meseta” is spotted by more than 1500 shallow lakes which are28 regularly used by waterbirds and support one of the main29 breeding populations of the threatened Hooded Grebe (Podiceps30 gallardoi). We collected data on bird presence and abundance31 at the species level in 41 shallow lakes, covering a wide32 spectrum of the wetland environmental variability found in the33 area. We conducted six surveys from spring to fall between34 2004 and 2006. We recorded a total of 18 waterbird species,35 which represent five and six different families and orders,36 respectively. Anatidae was the family most represented with 1237 species, accounting for 85% of the observed waterbirds.38 Waterbird distribution among lakes was variable, from 2.8%39 occupied lakes for the Wilson’s Phalarope (Steganopus40 tricolor) and Andean Duck (Oxyura ferruginea) to 80% for the41 Black–necked Swan, and abundance varied greatly both between42 species and seasons. The threatened Hooded Grebe, in43 particular, was recorded in 14 lakes (1–81 individuals). Six44 species bred in the area: Hooded Grebe, Flying Steamer–duck45 (Tachyeres patachonicus), crested duck (Anas specularioides),46 Silvery Grebe (Podiceps occipitalis), Upland Goose (Chloephaga47 picta), and White–winged Coot (Fulica leucoptera). Hooded48 Grebes nested at four lakes, three of them not previously49 known to hold breeding birds. Results point to the need of50 further studies on the dynamic nature of waterbird lake use to51 adequately assess the importance of the Lake Strobel Meseta as52 waterbird habitat.