BIOLOGY OF BLACK OYSTERCATCHERS BREEDING ON TRIANGLE ISLAND, BRITISH COLUMBIA, 2003-2011.

摘要

The breeding biology of the Black Oystercatcher (Haemotopus bachmani) was studied on Triangle Island, British Columbia, Canada in 2003-2011. Breeding density at this remote site was relatively high, ranging from 2.23 to 3.72 pairs/km of shoreline in the 9 y. Most clutches were initiated in the last 2 wk of May, and the annual mean 1st clutch size ranged from 2.1 to 2.8 eggs/ nest, values similar to those recorded at other sites. Egg size differed little in clutches of 1, 2, and 3 eggs. Hatching success at Triangle Island ranged from 55 to 87% in 5 y, which is on the high end of the range compared to other sites. Limited data suggested that adult survival rates exceeded 90% per annum, and 43% of individuals banded just prior to fledging survived through at least their 1st winter. Oystercatchers are reliable indicators of the health of coastal ecosystems, and these data comprise a baseline against which future changes at Triangle Island can be assessed.