Breeding Habitat Use by the Red-legged Cormorant (Phalacrocorax gaimardi) in Patagonia, Argentina

Abstract

Abstract Twelve colonies where the Red-legged Cormorant (Phalacrocorax gaimardi) breeds in Argentina were visited. Physical and biological characteristics were recorded at 29 nesting cliffs and at different sectors within cliffs. Forty-five percent of the cliffs were located on continental shores, the rest were on islands. Cliff height and length varied (mean height = 14 ± 5 m, length range = 12 to 3,000 m) but their slope was commonly 80 to 90°. Most cliffs had more than 50% of the total available area with apparent suitable breeding sites. Cliff length and available area was positively correlated with the number of nests. Forty-nine different sectors used by Red-legged Cormorant on the cliffs were identified. In those sectors, number of active nests was positively correlated and nest density negatively correlated with area. Highest median density of nests was NE in orientation, protected from predominant winds. Minimum average distance from the tide line to the closest nest group was positively correlat...