Sunday, August 29, 2010

Metro Beach banding report - August 27-28, 2010

After last week's modest cold front, I had high hopes for good warbler movement this week, and of course reduced mosquito activity in the somewhat cooler temperatures. There was some success on both fronts, with fewer individual warblers than expected but with some interesting species, and fewer mosquitos although insects did provide some entertainment, which I'll cover at the end of this post. While pretty good numbers were banded these two days, more than half of them were American Goldfinches, so anyone hoping to see more goldfinch photo highlights should stop reading here to avoid disappointment.

Banding highlights from Friday, August 27 included two Ruby-throated Hummingbirds and the first Red-eyed Vireo of the season, an after hatch year based on its brown eye, and sexed as female based on the short length of its wing.

Red-eyed Vireos have had an interesting banding history at Metro Beach. Between 1990-1999 a total of 20 was banded in spring (average 2.0 per spring), with a peak of 10 in the spring of 1996. Between 1989-1999 a total of 112 was banded in fall (average 10.2 per fall), with a peak of 22 in fall 1991. Since I restarted this project in 2004, I have banded a total of 22 Red-eyed Vireos here, all in fall, averaging only 4.4 per fall. I dno't necessarily think that they're less common than before, but certainly I'm catching fewer of them. The undergrowth has changed, and I think this is due to the increase in White-tailed Deer in the park. Up to 1999, deer were rather scarce, but since 2004, they've been quite common (I'd use the word nuisance, due to the damage they do to nets, vegetation, and other wildlife).

Eight species of warbler were banded today, including Nashville, Magnolia, Ovenbird, Northern Waterthrush, Common Yellowthroat, and Wilson's Warbler.

Hatch-year female Nashville Warbler

The first American Redstart of the season was banded, as well as the first Black-throated Blue Warblers.

Even hatch-year male Black-throated Blue Warblers, like the one above, are easy to identify as they closely resemble adults, usually showing a more mottled black-and-white throat. One of my favorite "quiz birds" to puzzle the banding volunteers with, as well as birders passing by, is the bird shown below.

Even fairly experienced birders can be fooled by a bird like this. The main field mark, due to variation between individuals, is pretty much absent. Now what!  All too often a dependency on a single well-defined field mark can let us down when it isn't there. This is a hatch-year female Black-throated Blue Warbler, which nearly lacks the white mark at the base of the primaries (like the male above has). But the facial pattern of this bird is fairly distinctive too. The rather dusky cheek, narrow white supercilium, and white arc below the eye, coupled with the pale yellow underparts, uniform greenish upperparts with no wing bars, should get you to the right ID.

Interesting birds observed but not banded today included a Belted Kingfisher flyover, a couple of Swainson's Thrushes giving their nocturnal flight calls from the woods away from the nets, and a beautiful adult male Canada Warbler.

Banding highlights from Saturday, August 28 included three Ruby-throated Hummingbirds, and an Eastern Wood-Pewee, a species that is infrequently captured here.

Note that this individual can be aged by the relatively narrow whitish-buff wing bars, where a hatch-year bird will have much broader and richer buff, almost cinnamon, wing bars that it can retain well into the fall. Many younger birds, in my limited experience, can have an almost completely dark lower mandible, which might prompt reports of Western Wood-Pewee, a difficult ID even in-hand. I noted that this adult had a fairly extensive duskiness on the lower mandible too, perhaps more than many Eastern Wood-Pewees.

For those less interested in the esoteric ID points of pewees, the photo above provides an excellent view of the stiff rictal bristles characteristic of all Tyrant Flycatchers.

Another flycatcher captured today provided some interest. It was an Empidonax, but clearly a juvenile as it had a short tail. At this locale, Point Rosa Marsh at Metro Beach Metropark, Willow Flycatchers are annual breeders, but Alder Flycatchers do nest some years. This summer I did not detect any Alders here, and indeed there have been several Willow Flycatchers all around the Field Nets since the beginning of the fall banding season. I think that it is reasonable to say that this is a recently fledged Willow Flycatcher.

Something else about this flycatcher struck me as interesting. Though this is only the second juvenile Empidonax I've banded (the first was in August last year), it seemed to have a rather pale upper mandible as well as lower. Perhaps this is due to its young age?

The first Marsh Wren of the season (a hatch-year) was captured. As expected, it was nowhere near the cattail marsh where they nest, but in the "upland" woods across the road. In recent years, it has become clear that this species disperses into adjacent areas and habitats after breeding at this locale, suggesting that preservation of surrounding lands in addition to wetlands is important to the biology of Marsh Wrens.

Rose-breasted Grosbeaks are very infrequently banded at Metro Beach, and this hatch-year female was a surprise out in the Field Nets early in the morning.

Among the 9 species of warbler captured today (8 banded, Ovenbird was a recapture), the Yellow Warbler was possibly one of the last we'll see this season. But the hatch-year female Connecticut Warbler was definitely a highlight of the season, as this is only the fourth since 2004, all in fall (8 were banded from 1989-1999, 6 in fall).

Interesting birds observed today but not banded included two Common Nighthawks at dawn over the beach, Swainson's Thrushes again heard giving nocturnal flight calls from nearby woods, a Great Horned Owl giving begging calls before sunrise, and a Cape May Warbler sitting in the tree in the middle of the Field Nets...too bad it didn't go in.

It has also been an interesting summer, and early fall for insects, especially butterflies and dragonflies. A number of southern species have moved north including the very beautiful Buckeye butterfly, which was one of 13 butterfly species found in the banding area on these two days.

Another southern immigrant, much smaller but still beautiful, is the Fiery Skipper, which also delighted us out by the Field Nets.

Banding on these two days could not have been done without the capable help of the following volunteers: Melissa Brady, Mary Buchowski, Kevin Hannay, Dave Lancaster, Tom Schlack, and Jeff Silence. Thank you!

Banding Data
FRIDAY, August 27, 2010
Sunrise (E.S.T.): 5:51
Time Open (E.S.T.): 5:45
Time Closed (E.S.T.): 13:00
Hours Open: 7.25
No. of Nets: 4.25-13.25
Net Hours: 87.813
Temperature (F): 53-77
Cloud Cover: 10-0%
Wind: WSW-SE @ 1-3-10 mph
Barometer: 29.85-29.82
Precipitation: None
No. Banded: 72 (plus 7 recaptures and 3 released unbanded)
No. of Species: 16
Capture Rate: 93.4 birds per 100 net hours
Volunteers (worked 10.0 hours, 6:00-16:00): Dave Lancaster, Tom Schlack.

Ruby-throated Hummingbird - 2
"Traill's" Flycatcher - 1
Least Flycatcher - 1
Red-eyed Vireo - 1
House Wren - 3 (plus 1 recaptured)
Nashville Warbler - 1
Magnolia Warbler - 4
Black-throated Blue Warbler - 2
American Redstart - 1
Ovenbird - 2
Northern Waterthrush - 1
Common Yellowthroat - 5
Wilson's Warbler - 2
Song Sparrow - 6 (plus 2 recaptured and 1 released unbanded)
Northern Cardinal - 1
American Goldfinch - 39 (plus 4 recaptured and 2 released unbanded)
SATURDAY, August 28, 2010
Sunrise (E.S.T.): 5:52
Time Open (E.S.T.): 5:45
Time Closed (E.S.T.): 13:00
Hours Open: 7.25
No. of Nets: 4.25-13.25
Net Hours: 89.063
Temperature (F): 63-84
Cloud Cover: 0%
Wind: SW-S @ 5-7-10 mph
Barometer: 29.86-29.87
Precipitation: None
No. Banded: 50 (plus 12 recaptures)
No. of Species: 19
Capture Rate: 69.6 birds per 100 net hours
Volunteers (worked 10.0 hours, 6:00-16:00): Melissa Brady, Mary Buchowski, Kevin Hannay, Jeff Silence.

Ruby-throated Hummingbird - 3
Eastern Wood-Pewee - 1
Willow Flycatcher - 1
Black-capped Chickadee - 1 (plus 1 recaptured)
House Wren - 1
Marsh Wren - 1
Nashville Warbler - 1
Yellow Warbler - 1
Chestnut-sided Warbler - 1
Black-throated Blue Warbler - 1
American Redstart - 1
[Ovenbird - 1 recaptured]
Northern Waterthrush - 3
Commnon Yellowthroat - 1
Song Sparrow - 2
Northern Cardinal - 1
Rose-breasted Grosbeak - 1
American Goldfinch - 28 (plus 10 recaptured)

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