A new breeding location for Wedge-rumped Storm-Petrels (Oceanodroma tethys kelsalli) in Peru

Abstract

Two subspecies of the Wedge‐rumped Storm‐Petrel (Oceanodroma tethys) have been recognized, one that breeds on the Galapagos Islands (O. t. tethys) and a second that breeds on islands off the coast of Peru and Chile (O. t. kelsalli). We report a breeding colony of Wedge‐rumped Storm‐Petrels (O. t. kelsalli) on Ferrol Island, Peru. We observed 176 nests on 1–2 May 2006, including 55 (31%) with nestlings and 87 (50%) with eggs. Assuming an incubation period of 40–50 d, the first eggs would have been laid in mid‐March. We found that O. t. kelsalli returned to land over a period of several hours at night. In contrast, O. t. tethys, the Galápagos subspecies, is apparently diurnal, with maximum activity during the midmorning hours. This difference in behavior may permit the exploitation of different food resources. The Peruvian government has not listed the Wedge‐rumped Storm Petrel as a threatened species because of a lack of information about its population status. However, our observations suggest that Ferrol Island is an important breeding area for this storm‐petrel.

Una colonia reproductiva de la Golondrina de la Tempestad Peruana, Oceanodroma tethys kelsalli (Lowe 1925), en la Isla Santa, Perú

“…This difference was unexpected, given that the breeding season of this taxon is in autumn (Spear & Ainley 2007). In Peru the peak of laying is in April and May (Ayala et al 2004, Ayala & Sanchez-Scaglioni 2007. In Chile, the first egg laying may occur in late December (Bernal et al 2006).…”

“…1), are important breeding localities of the Wedge-rumped Storm petrel (Ayala et al 2004, Ayala & Sanchez-Scaglioni 2007 (Table 3). Santa is the biggest of this group of islands.…”

“…1). The Santa Island is administrated by PROABONOS (Special Project for the Promotion of the Use of Guano Coming from Seabirds), that regulates the disturbance to breeding of guano birds on Peruvian islands (Ayala & Sanchez-Scaglioni 2007).…”

“…Prior to this, the only known breeding localities were of the Wedge-rumped Storm-petrel Oceanodroma tethys kelsalli. In recent years, additional storm petrel colonies have been discovered along the Peruvian and Chilean coast, although very little is known about the breeding biology and numbers of these birds (Jahncke 1992, Schlatter & Marin 1983, Simeone et al 2003, Ayala et al 2004, Bernal et al 2006, Ayala & Sanchez-Scaglioni 2007.…”

“…In Chile, a small breeding colony was reported on Isla Grande (Simeone et al 2003, Bernal et al 2006. In Peru, Ayala et al (2004) found 100 pairs breeding in crevices along dry-stone walls on Chao and Corcovado Islands and Ayala & Sanchez-Scaglioni (2007) found 176 nests on nearby Ferrol Island in Chimbote bay. That specie is not protected by Peruvian Government because of lack of information.…”