Spring banding 2002 took place on 31 days from 16 April to 31 May. We lost six days to weather. Nets were open an average of 5 hours per day with an average of 20 nets (12 meter equivalent1). We banded 830 new birds and had 218 recaptures. A total of 1137 birds were netted (this includes birds released unbanded). Our capture rate was 36.7 birds per 100 net-hours. Previous spring means are 526 new birds and 651 total, and 42.0 per 100 net-hours. Thus, it was an outstanding season.
We completely missed a few easy species — Golden-crowned Kinglet, Fox Sparrow, Philadelphia Vireo, and Tennessee Warbler are stand-outs — yet we finished the season 74 species. With a previous spring mean of 62 species, this was a spring-season high for us, a total we often don’t reach even in the fall. Unusual species captured this spring included Summer Tanager (our second), Clay-colored Sparrow (our third and first spring capture), Black-billed Cuckoo, two Connecticut Warblers, Purple Finch (first spring capture), and “Brewster’s” Warbler. We also banded a number of species that typically hang out over the height of our nets: three Great Crested Flycatchers, Scarlet Tanager, and Eastern Wood-Pewee. The prolonged cold spring meant many birds were foraging closer to (or on!) the ground, contributing to many new high totals.
Here are some species with a more than 100% increase from previous spring means; these are raw numbers not adjusted to capture effort (number of birds per net-hour). Numbers are total followed by previous spring mean, and deviation from mean.
* Orange-crowned Warbler (7, 1.3, +438.5%)
* Nashville Warbler (36, 8.3, +333.7%). This follows a 400% increase last fall, and a 188% increase in fall 2000. In fact, this species shows a true increase, in birds per net-hour, over the 9 of the last 10 spring seasons.
* Wilson’s Warbler (28, 8.2, +241.5%).
* Veery (18, 5.4, +233.3%).
* Least Flycatcher (21, 8.0, +162.5%).
* Yellow Warbler (37, 16.7, +121.6%).
Recoveries and returns
We received news of one of our banded birds being recovered elsewhere: an American Goldfinch banded on 10 May 2001 was killed by a cat in Berea, KY on 12 May 2002. Let me just say: Please visit the Cats Indoors! site of the American Bird Conservancy.
We had returns a’plenty (migrant birds banded here in a previous year). Our favorite was a male Wood Thrush banded in 1997 that has nested here each year since. He is color banded pink over pink…does he need to prove his masculinity?
A total of 117 Gray Catbirds have returned to UM-Dearborn since 1992. The oldest birds to return this year were three banded in 1998 — each has been back every year. Also interesting were some recaptures of resident birds, including a Blue Jay, a Northern Cardinal, and a Downy Woodpecker all from 1995. Another cardinal originally banded in 1994 was found dead on one of our trails.
The survey says…
Our surveys turned up some nifty birds, with 145 species, including 30 species of warblers, recorded between 1 March and 31 May. The rarest was a Mississippi Kite first found by Rick Crossland on 9 May. It was seen the next day by Rick Simek and the majority of the Field Biology class! The Northern Bobwhite at left was a one-day wonder and the first on campus in many years. An Olive-sided Flycatcher was cooperative for six days. Other unusual species included Cerulean and Hooded Warblers, and three different Prothonotary Warblers. The species “missing in action” was Tennessee Warbler. Usually abundant, we had a few but most must have blown by us. Conversely, Blackburnian Warblers were unusually common, with up to six seen on many days.
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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 manageable numbers. ↩