Rock Shag(Phalacrocorax magellanicus) nest in the cliff walls of San José and Nuevo gulfs, forming important colonies. In Puerto Piramides you can visit a colony on whale watching excursions or boat excursions near Punta Piramides.
Reproductive Cycle Overall, the nesting cycle begins in early October when adults begin to occupy and rebuild the nest. The egg laying starts between the last week of October and early November, in the Chubut colony, as in Santa Cruz. The egg laying is completed in periods ranging from four to twelve weeks from the laying of the first eggs. The chicks hatch between the months of November and December and fledge between late January and February. This species is not migratory, so most Black Rock Shag breeding adults remain throughout the year in nesting colonies or in the surrounding areas.
Their diet consists mainly of benthic fish (those living near the bottom) and to a lesser extent, a few species of pelagic fish (those that move in large schools) and marine invertebrates (cephalopods, polychaetes and crustaceans). It usually feeds in shallow water (no more than 10 m) and offshore (no further than 5 km).