Rw. Butler, Winter abundance and distribution of shorebirds and songbirds on farmlandson the Fraser River delta, British Columbia, 1989-1991, CAN FIELD-N, 113(3), 1999, pp. 390-395
The winter distribution of common shorebirds and songbirds in farmlands on
the Fraser River delta, British Columbia, is described for 1989-1991. Most
Dunlin (Calidris alpina) and Black-bellied Plovers (Pluvialis squatarola) r
oosted in large flocks (median=6450 birds) on beaches during high tides. Sm
aller flocks (median=507 birds) that flew to farmlands sealed in ploughed f
ields, turf grass and pasture within 2 km of Boundary Bay. Dunlin and Black
-bellied Plovers that flew to farmlands mostly foraged there between Novemb
er and March. The seasonal use of farmlands by Dunlins is probably a trade
off between food energy requirements and predation risk from falcons. Forty
-five species of songbirds were recorded in farmland hedgerows. Song Sparro
w (Melospiza melodica), American Robin (Turdus migratorius), White-crowned
Sparrow (Zonotrichia leucophrys), and European Starling (Sturnus vulgaris)
accounted for over two-thirds of all birds recorded. Shrub hedgerows suppor
ted 30 species with a mean of 7.9 individuals detected per census stop vers
us 40 species with a mean of 18.0 individuals per census stop in tree-hedge
rows.