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Rouge River
Bird Observatory Spring banding 2004 |
| Overview Spring
banding 2004 took place on 31 days from 15 April to 3 June.
An average of 18 nets (12 meter equivalent*) were
open an average of 5.4 hours per day. We lost five whole and eight partial
days to bad weather. It was the rainiest May on record (8.46" at
Metro airport), but often our closures were due to wind. Mean starting
wind speed was 7.6 MPH, not great for banding. One day we had to
close when it started to snow quite hard. I think this is a first
for a spring banding season.
We banded 639 new birds and had
113
recaptures of 64 species (includes Ruby-throated Hummingbird
and House Sparrow, which are not banded). A total of 788
birds were netted (this includes birds released unbanded). Our
capture rate was 31.3 birds per 100 net-hours. Here's
a quick comparison of this year versus previous spring means --
Highlights
Probably due to flooded conditions in the banding lanes, numbers of some ground-foraging species were down on a pernet-hour basis: Song Sparrow -36.4%, White-throated Sparrow -12.5% (although present in huge numbers away from the banding site), and Swainson's Thrush -11.2%. The same conditions probably contributed to a boost in a couple of species that like wet conditions: Common Yellowthroat +44.4% (after a large increase last fall) and Swamp Sparrow +56.8%. Magnolia Warblers were up modestly (27.7%). The biggest gainer was Lincoln's Sparrow. With 33 banded versus a 12-year spring mean of 12.9, they were up 108.1% per 100 net-hours. These were the most interesting trends for species with decent sample sizes. Hooded Warblers are annual here,
but always a treat. A female banded on 16 May was only our
For totals of all species, their previous fall means, and the total since 1992, click here. Bird sightings
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*In order to compare different locations or years that may operate the same number of hours but with more or fewer nets, capture rate is calculated by "net-hours." One net hour is one 12-meter net open one hour, or two 6-meter nets open one hour, etc. This rate is often expressed per 100 net-hours for more managable numbers.