Abstract

AMOROS KOHN, Samuel; SARAVIA GUEVARA, Patricia  and  WILLIAMS, Marta. Breeding biology of Sternula lorata, peruvian tern, Paracas National Reserve (PNR), Ica - Peru. Ecol. apl. [online]. 2010, vol.9, n.2, pp.125-132. ISSN 1726-2216.

The Peruvian Tern is an endemic bird to the Humboldt Current. Its population, currently estimated to be from 1 000 to 2 499 individuals is declining worldwide. The research was conducted at the Paracas Peninsula from November 2006 to July 2008. Nests were located and marked and the reproductive biology of the species was described. Two breeding sites of the Peruvian Tern were located: 1) Pampa Lechuza and 2) Pampa Atenas - Cequión. In both places, and as a cumulative result of the two breeding seasons, 60 nests were found. The nests consist of a depression with the following dimensions: 10.46 cm (n = 44 ±1.89) of greater diameter; 9.56 cm (n = 44 ±1.70) of smaller diameter and 1.56 cm (n = 44 ±0.44) of depth. They were found in areas with an altitude less than 100 m.a.s.l. and were associated with the presence of stones, bones, shell and / or some combination of these elements. The distance between two active nests varied from 44.18 m to 3.28 km and the distance of nests to the sea varied from 1 km to 3.7 km. This species lays mostly 1 to 2 eggs per nest. The eggs were 31.84 mm (n = 82 ±1.44) long by 23.88 mm (n = 82 ±0.82) wide. The reproductive success of the 2006 - 2007 breeding season was 55.6 % for those nests in which at least one egg hatched. The Peruvian Tern has fidelity to the nest and / or nesting site and presents an asynchrony in reproduction.

Keywords : Reproductive biology; Peruvian tern; Sternula lorata; Paracas; reproductive success; characteristics of the nests.

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