Tuesday, April 19, 2011

April 19 - Spring Migration Monitoring

Our Spring Migration Monitoring program wrapped up on April 14, after three exciting weeks watching spring unfold. The program was very successful documenting the arrival dates and migratory movements for several species. Exciting moments included catching two Northern Saw-whet Owls on the first net round, hearing a Upland Sandpiper flyover, and catching over 130 birds on April 12.

Migration was slow over the first week, with Song Sparrows slowly building in numbers and waves of Tree and Violet-green Swallows passing through. Northern Shrikes were seen throughout the first week, but it appeared that this involved new birds arriving every few days. A few more of the wintering Yellow-rumped Warblers were banded and others recaptured, overlapping with the arrival of spring migrants.

The second week was showed a definite increase in the number of birds around. A number of Red-winged Blackbirds were caught this week, which seemed unusual as they had been around since the end of January, but had stayed largely in the marsh. Most often it was a mixed flock of females and males, perhaps caused by males pursuing females as the prospect for potential mates. The first interesting bird during this period was a Northern Saw-whet Owl caught on April 1st, but a Northwestern Crow captured on April 3rd was the first for the station and surprized all who were present. April 5th saw a fall-out of Violet-green Swallows with over 50 banded that day.

The third week of monitoring saw migration really pick up with the first arrivals of Caspian Tern on the 7th, N. Rough-winged Swallow on the 8th, Orange-crowned Warblers on the 11th, Common Yellowthroats on the 13th, and Yellow-headed Blackbird on the 8th. Large numbers of Violet-green Swallows and Audubon's Warblers were banded during this period, especially over the 13-15th. Another N. Saw-whet Owl was caught on 12th, which is quite intriguing, raising the possibility that a spring movement may occur in early April along the coast. The most interesting bird was a flyover Upland Sandpiper on April 12th, which was the first spring record for the Vancouver area.

Overall, 433 birds were banded and 205 were recaptured of 26 species. Many days of wind and rain resulted in reduced net hours and banding only occurring on 16 days. The species totals for the birds banded are listed below:

N. Saw-whet Owl2
Downy Woodpecker12
Rufous Hummingbird12
Tree Swallow24
Violet-green Swallow14311
N. Rough-winged Swallow3
Barn Swallow1
Northern Shrike1
Marsh Wren88
Pacific Wren11
Black-capped Chickadee310
Northwestern Crow1
Ruby-crowned Kinglet1013
Golden-crowned Kinglet3
American Robin541
Orange-crowned Warbler51
Audubon's Warbler63121
Myrtle Warbler42
Unk. Yellow-rumped Warbler41
Common Yellowthroat2
Spotted Towhee213
Song Sparrow61662
Lincoln's Sparrow871
Fox Sparrow1154
Golden-crowned Sparrow17
Oregon Junco5
Red-winged Blackbird502
House Finch1
American Goldfinch101

A big thank you goes out to all of our volunteers for helping complete our program. We are now taking a bit of a break, but will be starting our Breeding Bird Monitoring program in late May, so stay tuned for updates.

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