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A Blue-winged Warbler
(left) and Golden-winged Warbler (right) were among the birds banded this
fall.
Overview
Fall banding 2001 took place on 47 days
from 15 August to 4 November. It was a rainy, windy fall. For
September and October combined, total rainfall was 6 inches above average!
This resulted in us losing 16 whole and 9 partial days to rain, or brisk
winds. An average of 20 nets (12 meter equivalent*)
were open an average of 4.4 hours per day.
We banded 1763 new birds and had
451
recaptures. A total of 2424 birds were netted (this
includes birds released unbanded). This broke our previous fall record,
set last year, of 1526 new birds and 1961 birds netted, and represented
the first season we broke the 2000-bird mark. Our capture rate was
58.3
birds per 100 net-hours. Previous fall means are 1117 new
birds and 1410 total, and 54.4 per 100 net-hours.
Our best day was no doubt 15 October. We
banded 202 new birds and 8 recaptures; 180 of the birds were Yellow-rumped
Warblers. This eclipses our previous daily high total
by nearly 100 birds!
Numbers and trends
This fall, 70 species (plus 3 not banded)
were handled. Our record is 75 and we thought we might be able to hit it,
but missed out on some species that aren't usually too hard to get: Red-breasted
Nuthatch (despite it being a good invasion year), Brown Thrasher, Brown-headed
Cowbird, Red-winged Blackbird (although many dozens were lurking near our
nets!), and Baltimore Oriole.
The breeding season was extremely hot and
dry. We wondered what impact that would have on productivity, and
thus the numbers of young birds coming through. We certainly saw
evidence that the drought was tough on young birds, as over 35 showed fault
bars on their feathers, compared to a fall average of about 10! To
learn more about fault bars (right) and what they tell us, click
here. That aside, most birds seemed to be banded in roughly
average numbers. Only a couple of species showed marked declines
from previous fall means (total followed by previous fall mean, deviation
from mean):
American Redstart (11,
21.2, -48%)
White-throated Sparrow
(51, 91.2, - 43.4%)
The Black-capped
Chickadeeinvasion that overwhelmed some banding stations in
the northeast did not materialize here (we're not complaining!).
We banded 31 new chickadees, only 10 above the previous fall mean.
We
did band some species in excellent numbers. Winter
Wrens (left) furnished the real fall story. The 9 we banded
was 900% above the previous fall mean of 0.9; in the ten years of RRBO
history, we'd only banded a total of 8 before this fall! They popped
up (literally) in many of our fall surveys as well, so it was just a good
year for these cute little birds. The 696% increase in
House
Finches (39 banded) was a mystery. While they are
hitting the feeders at the new interpretive center, we did not capture
them in nets anywhere near the feeding stations.
A few other species with increased numbers:
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Philadelphia Vireo (10,
3, +233.3%)
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Nashville Warbler (41,
17.7, +131.6%) +400%). This follows an increase of 400% this spring
and 188% last fall.
-
Common Yellowthroat
(19, 5.8, +227.6%)
For totals of all species, their previous
fall means, and the total since 1992, click
here.
Returns
Thirty
birds banded in previous years were recaptured this fall. Easily
the most remarkable was a White-throated Sparrow
(left) originally banded on 23 October 1998 which we recaptured on 4 November
2001! Migration stopover site fidelity is rarely documented, so this
was an exciting recap! Runner up was a Red-eyed
Vireo originally banded on 24 August 2000 that was recaptured precisely
one year later, after a Peruvian winter vacation and Dearborn-area breeding
season.
Our oldest recaptured Black-capped
Chickadee was one originally banded as a juvenile on 15 August 1996.
It has landed in our nets 16 times since then. Other slightly old
birds were an American Goldfinch and a Northern
Cardinal that were each originally
banded in 1997.
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