Sunday, October 16, 2011

Metro Beach banding report - October 12 & 14, 2011

This past week was rainy and windy, with a decrease in birds but still some interesting captures. On Wednesday, October 12, the strong winds were from the NE switching to SE, resulting in an exponential increase in leaves falling into the nets, but it did not affect the nets to the point of forcing the station to close. But the rain starting just before noon (EDT) did force us to close early. On Friday, October 12. rain in the morning delayed setting up for about an hour, while increasing winds did eventually force the station to close early as well. The large movements of White-throated Sparrows and Hermit Thrushes expected at this time of year seem to have passed us by, or haven't arrived yet.

Highlights of the 43 birds banded on Wednesday, October 12 included a flycatcher; an Eastern Phoebe. I don't normally catch very many phoebes in spring (max 7) or fall (max 5). I was hoping to show the all black bill of this species in the photo, but he just wouldn't keep his mouth shut! Normally, I work with a bird to get the photo I want for about a minute and, if I can't get it, release the bird.

Hatch-year Eastern Phoebe

It was easy to age this bird based on the "molt limit" visible in the greater secondary coverts. In the photo below, the arrows point to the brighter buffy juvenile coverts contrasting with the paler-tipped "first basic" coverts.

Hatch-year Eastern Phoebe

There were very few kinglets in the banding area, somewhat unexpected for this time of year, and only a few thrushes which included a somewhat late Gray-cheeked. Only four warbler species were in the banding area today, with singles of two species banded, Nashville and Black-throated Blue.

Hatch-year female Black-throated Blue Warbler

Sparrows dominated today, as they will for the remainder of the season. Not one, but two Field Sparrows were nice to see. This species isn't captured at this station every year, and this is the first time every with two in the same season, and only the 6th and 7th banded here since 2004 (plus 4 from 1990-1993).

Hatch-year Field Sparrow

White-crowned Sparrow is in the highlights again this week partly because it appears to be a good season for them, and partly because of two special individuals captured today. There are about 5 subspecies of White-crowned Sparrow recognized, with the Eastern (subspecies leucophrys) the dominant form in our area. Along the southern shores of Hudson Bay and westward is another form, Gambell's (subspecies gambellii) that is a rare but annual migrant through Michigan (sometimes fairly common at Whitefish Point in the Upper Peninsula). I have banded a handful of hatch-year Gambell's over the years, and probably as many or more intergrades, but today was the first adult Gambell's I've ever banded anywhere.

After hatch-year "Gambell's" White-crowned Sparrow

The streaking on the back is more contrasting in Gambell's than in Eastern, but the main differences are on the head, as shown in the comparison photo below.

"Gambell's" (top) and "Eastern" (bottom)
White-crowned Sparrows (both AHY)

Most obviously, the black supraloral of Eastern is absent in Gambell's, and the bill is slightly paler. Right next to this adult Gambell's, in the same net run, was a clear-cut hatch-year Gambell's as well, shown below compared with a hatch-year Eastern.

"Gambell's" (top) and "Eastern" (bottom)
White-crowned Sparrows (both HY)

Interesting birds observed but not banded included a calling Great Horned Owl before dawn, a couple of Winter Wrens in the undergrowth, a somewhat late Common Yellowthroat, and two Dark-eyed Juncos.

Highlights of the 45 birds banded on Friday, October 14 included two Brown Creepers. As mentioned in last week's posting, there has been some discussion among North American banders with European ringers on ageing them by the pale buffy spots on their longest primary coverts (larger in adult Common Treecreeper, smaller in hatch-year). But ageing Brown Creepers by skull becomes tricky as after October 1 ossification can be completed, making it very difficult (or impossible) to age a bird as after hatch-year at this time. The wings of today's two birds are shown below. One was clearly a hatch-year with "incomplete" skull ossification (and small pCov spots), while the other had completed its skull ossification (and shows larger pCov spots).

Possible after hatch-year Brown Creeper

I also noticed two different colors of median secondary coverts on this apparent adult (above), which can be seen just below my finger. Is this a molt limit? Maybe this is actually a hatch-year bird and the larger primary covert spot is not indicative of age? No answers yet to these questions...

Hatch-year Brown Creeper

There was another influx of Yellow-rumped Warblers today (18 banded), bringing the season's total to 47, the highest since I restarted banding at this station in 2004, and the third highest ever (77 in fall 1991, 60 in spring 1996).

After hatch-year female
Yellow-rumped (Myrtle) Warbler

Banders in the northeastern U.S. and eastern Canada have noted much lower numbers this fall (so far anyway). In eastern Canada, a two-year cycle has been detected. The Yellow-rumps banded so far at Metro Beach have consisted of a larger than expected number of hatch-year birds, so perhaps there was a poor nesting season? Another possibility is that we've been having more northeasterly winds than is typical for this time of year, which may have pushed some of eastern birds into the Great Lakes instead? One hatch-year Yellow-rump banded today had a several deformed bill.

Hatch-year male Yellow-rumped (Myrtle) Warbler
with deformed bill (inset shows bill from below)

The only other warbler banded today was a Palm Warbler.

Hatch-year (Western) Palm Warbler

A non-avian highlight today was this small frog, found hopping across the trail. I believe it is a Striped Chorus Frog (Pseudacris triseriata), but I've never seen an orange one before! The field guides say they can be brown, which I suppose this one is brown, but it was more colorful than expected.

Striped Chorus Frog (Pseudacris triseriata)

Interesting birds observed today but not banded included a Turkey Vulture (this species has been unusually scarce in the park this year), at least 3 Winter Wrens, a somewhat late Swainson's Thrush, the first flock of Cedar Waxwings in the area since August, and an Eastern Towhee.

Banding could not have been done this week without the help of volunteers who have been most generous with their time: Jeremy Joswick, Dave Lancaster, Marie McGee, Tom Schlack, Jeff Silence, and Joan Tisdale.

Banding Data
WEDNESDAY, October 12, 2011
Sunrise (E.S.T.): 6:41
Time Open (E.S.T.): 6:00
Time Closed (E.S.T.): 11:15 (rain forced early close)
Hours Open: 5.25
No. of Nets: 4.50-13.50
Net Hours: 65.125
Temperature (F): 61-61
Cloud Cover: 50-100%
Wind: NE-SE @ 3-5-12 mph
Barometer: 30.02-29.98
Precipitation: Trace (light rain after close)
No. Banded: 43 (plus 15 recaptured and 4 released unbanded)
No. of Species: 15
Capture Rate: 95.2 birds per 100 net hours
Volunteers (worked 8.5 hours, 5:00-13:30): Jeremy Joswick, Jeff Silence, Joan Tisdale.

Eastern Phoebe - 1
Ruby-crowned Kinglet - 3 (plus 1 released unbanded)
Gray-cheeked Thrush - 1
Hermit Thrush - 5
Nashville Warbler - 1
Black-throated Blue Warbler - 1
Field Sparrow - 2
Song Sparrow - 8 (plus 6 recaptured)
Lincoln's Sparrow - 1 (plus 2 recaptured)
Swamp Sparrow - 4
White-throated Sparrow - 5 (plus 3 recaptured and 2 released unbanded)
(Eastern) White-crowned Sparrow - 6 (plus 2 recaptured and 1 released unbanded)
(Gambell's) White-crowned Sparrow - 2
[Northern Cardinal - 1 recaptured]
[Red-winged Blackbird - 1 recaptured]
American Goldfinch - 3

FRIDAY, October 14, 2011
Sunrise (E.S.T.): 6:43
Time Open (E.S.T.): 6:45 (rain delayed open)
Time Closed (E.S.T.): 12:45 (wind forced early close)
Hours Open: 6.00
No. of Nets: 4.50-13.50
Net Hours: 69.00
Temperature (F): 55-59
Cloud Cover: 100-70-100%
Wind: W @ 7-10-15 mph
Barometer: 29.38-29.43
Precipitation: Trace at close
No. Banded: 45 (plus 9 recaptured)
No. of Species: 15
Capture Rate: 78.3 birds per 100 net hours
Volunteers (worked 9.5 hours; 5:00-14:30): Dave Lancaster, Marie McGee (7.25 hrs), Tom Schlack.

Downy Woodpecker - 1 (plus 1 recaptured)
[Black-capped Chickadee - 1 recaptured]
Brown Creeper - 2
Ruby-crowned Kinglet - 3
Yellow-rumped Warbler - 18
Palm Warbler - 1
Song Sparrow - 2
[Lincoln's Sparrow - 1 recaptured]
Swamp Sparrow - 3
White-throated Sparrow - 8 (plus 1 recaptured)
White-crowned Sparrow - 3 (plus 3 recaptured - one of them a HY Gambell's)
[Northern Cardinal - 1 recaptured]
[Red-winged Blackbird - 1 recaptured]
House Finch - 1
American Goldfinch - 3

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