Monday, January 17, 2011

January 15, 16 - Winter Songbird Monitoring

The Pineapple Express has arrived and we were treated to balmy temperatures and unfortunately rain on Sunday. With all the rain we have had lately the water levels in the woodlot have continued to rise, with some areas now under 1m of water. We were able to open one of our nets in the north end of the woodlot as one of our volunteers saved the day and brought out hip-waders this weekend.

Overall catch rates are down a bit from early December, but we still caught ~30/day, with recaptures hovering around 50%. Its hard to say if the new birds are ones that have avoided our nets so far this winter, or if they are 'recent' arrivals. Some may be of the latter. This past weekend at least six Yellow-rumped Warblers seen around the sewage lagoons, and only two had been seen in December. It is possible that these birds may have been floating around the Vancouver area this winter and have recently made it to Iona Island, or they may have ridden the southerly winds up from points slightly further south.

Speaking of birds that may have ridden up on southerly winds, two species that I was hoping for and did not see this weekend were Barn and Tree Swallow. Most people would never think to search for these species in the middle of winter in Vancouver. But, since the 1990's many Barn and Tree Swallows have been seen every winter along the Pacific coast from California to BC. They typically arrive on southerly winds and generally don't stick around too long. No one knows exactly why they do this, but its not just these species that are traveling around at odd times of the year. Cave Swallows have in late fall for the last dozen or so years ridden low pressure systems from Texas and Mexico up to southern Ontario and the northeastern US, before following the eastern seaboard south again. So far this winter there have been several reports of Tree Swallows from both Washington and Oregon, a couple of reports of Barn Swallows and one report of Cliff Swallows in Oregon. Its only a matter of time before swallows are back in BC, so keep your eyes open for them in coastal areas such as Iona Island or the Reifel Migratory Bird Sanctuary.

Banding highlights this weekend were a recapture Varied Thrush, originally captured on December 31, our first new Marsh Wren since the fall, and another two American Robins (perhaps also moving around with the recent warm weather). All sparrows caught this weekend were still extremely fat, indicating that they are continuing to do quite well despite the rain. Other interesting sightings have included the wintering A. Bittern and Virginia Rails, two N. Shrikes (both of which were banded), a Rough-winged Hawk (new for the station!), and two Lincoln's Sparrows.

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