Revista Chilena de Historia Natural 76 (2): 323-333, 2003
RESEARCH ARTICLE
Breeding distribution and abundance of seabirds on islands off north-central
Chile
Between 1999 and 2003 we collected information on the breeding distribution and
abundance of 12 seabird species occurring on nine islands off the coasts of north and central Chile (27°-33°S). The Peruvian booby
Sula variegata was the most abundant seabird with a breeding population of ca. 18,000 pairs concentrated in two islands,
followed by the Humboldt penguin Spheniscus humboldti with ca. 9,000 pairs, the largest colony being at Chañaral Island
with ca. 7,000 pairs. Kelp gulls Larus dominicanus bred at all the surveyed sites in colonies of variable size, ranging from
40 to 2,000 pairs. Peruvian diving-petrels Pelecanoides garnotii and Peruvian pelicans Pelecanus occidentalis
bred at restricted sites, but generally in large colonies. Magellanic penguins Spheniscus magellanicus, wedge-
rumped storm-petrels Oceanodroma tethys, Neotropical cormorants Hypoleucos brasiliensis, guanay
cormorants Leucocarbo bougainvillii, red-legged cormorants Stictocarbo gairmardi, band-tailed gulls
Larus belcheri and Inca terns Larosterna inca nested at few sites forming small colonies (from a few to 150
pairs). Two new breeding sites are reported for the Peruvian diving-petrel and nesting of the wedge rumped storm-petrel is confirmed
on the Chilean coast for the first time. Despite protective status, most of the islands showed human disturbance, derived mainly from
guano harvesting, egging and tourism. On at least five of these islands we were able to confirm introduced mammals including rats,
rabbits and cats. These factors are likely to be detrimental to seabirds and thus demand detailed assessment. Further comprehensive
ornithological surveys in other areas are needed so as to improve the scarce knowledge that we currently have on the seabird
populations along the Chilean coast.
Key words:
seabirds, breeding
colony, abundance, conservation, Humboldt Current, Chile
