Essentially solitary, but sometimes in flocks (Murphy 1936, Frere et. al 2002, Nasca et al. 2004). Red-legged Cormorants are efficient divers. They make foraging trips in inshore waters less than 15 m deep. Foraging consisted of short dives (27 ± 2 sec), followed by short intervals at the surface (9 ± 1 sec) (Frere et al. 2002).
Red-legged Cormorants are colonial. Aggressions subdued and overt fighting are common in south Chile but rare in Argentina (Frere, personal observations). Threat consists of silent, mild gape-thrust preceded or accompanied by lateral head-quivering often with retracted neck interspersed with ‘worrying’ nestmaterial (Nelson 2005).
Red-legged Cormorants are monogamous.
Social and interspecific behavior
Usually solitary, but sometimes in flocks (Murphy 1936, Frere et. al 2002, Nasca et al. 2004).
On the Argentinian coast, Kelp Gulls (Larus dominicanus) and Dolphin Gulls (Leucophaeus scoresbii) are the main predator of Red-legged Cormorants. Both prey upon Red-legged Cormorant eggs and chicks (Frere and Gandini 2001, Frere et al. 2005). In one colony, remains of Red-legged Cormorants were found in caves used by Culpeo Fox (Pseudalopex culpaeus), and fox tracks were observed at the base of cliffs (Frere et al. 2005). In Chile, the wild cat Kodkod (Oncifelis [or Leopardus] guigna) preys on eggs and young or Red-legged Cormorants (Frere and Ruiz, personal observations).