The Breeding Biology of the Peruvian Tern (Sternula lorata) in Peru

Abstract

Abstract The Peruvian Tern (Sternula lorata) is one of the rarest seabirds that breed on the barren desert plains of Peru and Chile. Unlike the majority of seabirds breeding in this region, Peruvian Terns nest in open areas on the mainland, where they are exposed to attacks by predators, mainly foxes (Pseudalopex spp.). Here, we describe the Peruvian Tern's breeding biology and examine its ecological adaptations to counteract high predation rates from data collected during the 1970s and 1990s at four localities in central-southern Peru: Puerto Viejo (12°34'S), Pampa Lechuzas (13°53'S), Yanyarina (15°26'S) and Mollendo (17°04'S). Egg-laying was asynchronous both within and among breeding groups, spreading from mid October to late January. Modal clutch size was two eggs, which were incubated for 22 d. Weight increment for two chicks during the linear section of the growth curve was 2.27 and 2.54 g/d. A complete body weight growth curve for one chick was fitted to the logistic equation with KL = 0.193 d-1, A...