Sunday, May 25, 2008

Thrushes and other Migrants at Bear Swamp

I spent today helping a friend with her MAPS banding station in Bear Swamp, near Dividing Creek in Cumberland County. Birders often work Route 555 heading out of Dividing Creek for things like Kentucky and Prothonotary Warblers and Summer Tanager - this is the general area we were in. The station is far off the road, but you don't need to venture into the bush to find great stuff here. Just mind the traffic, sand trucks in particular.

If there ever were a reminder about the importance of swamp forests in general, and Bear Swamp in particular, for migratory birds, today was it. Thrushes were everywhere - we banded many Gray-cheeked and Swainson's Thrushes, and two Veeries, all migrants bound for points north, as well as one Wood Thrush, which probably was a local. A lot of northbound migration is finished by May 25, but for these thrushes it is still going strong. Nonetheless, it is unusual to record either Gray-cheeked or Swainson's in double digits, Gray-cheeked in particular, unless you are listening to their flight notes overhead at night. I heard or had visuals on at least 10 of each species in the depths of the woods during the morning. Many were singing, and the Gray-cheekeds gave frequent flight calls throughout the morning. And these thrushes were loaded with fat deposits, emphasizing even more the quality of this habitat for migrants.

[The top photo below is of a Gray-cheeked, the bottom of a Swainson's. Note the Gray-cheeked's plain gray face and minimal, incomplete eye-ring compared to the warm tones and prominent eye ring and "spectacle" on the Swainson's . Photos by Don Freiday, click to enlarge.]

[Having a bird in the hand can sometimes help with i.d, though I often find it easier to i.d. free ranging birds because that's how I am accustomed to seeing them, and because behavioral, vocal and shape clues are more helpful. Note that P6, the 4th feather in from the outside of the wing, is emarginated on this Gray-cheeked Thrush, meaning it narrows down towards the tip on the outer web. The same feather is not emarginated on Swainson's - but it usually is for the rare Bicknell's Thrush, so other clues must be used. These thrushes have 10 primaries, but the outermost one is tiny and not visibile in this photo.]
Bear Swamp held many more birds than thrushes. Particularly enjoyable were multiple Kentucky Warblers, Acadian Flycatcher, and Prothonotary Warbler. Whip-poor-wills were deafening along Route 555 at dawn. . . and ticks abundant and mosquitoes deadly in the forest interior all morning, so stick to the roadside and be prepared for insects. My full list of non-banded birds is below; most of these were heard, and all can be heard from Route 555 in this area.

Location: Bear Swamp
Observation date: 5/25/08
Number of species: 36
Laughing Gull 5
Yellow-billed Cuckoo 3
Black-billed Cuckoo 1
Whip-poor-will 5
Hairy Woodpecker 1
Northern Flicker 1
Eastern Wood-Pewee 1
Acadian Flycatcher 5
Great Crested Flycatcher 1
Yellow-throated Vireo 1
Red-eyed Vireo 5
Veery 2
Gray-cheeked Thrush 10
Swainson's Thrush 10
Wood Thrush 5
Gray Catbird 1
Cedar Waxwing 10
Blue-winged Warbler 1
Northern Parula 1
Magnolia Warbler 1
Blackburnian Warbler 3
Yellow-throated Warbler 1
Pine Warbler 1
Blackpoll Warbler 5
Black-and-white Warbler 2
Prothonotary Warbler 1
Worm-eating Warbler 3
Ovenbird 5
Kentucky Warbler 5
Common Yellowthroat 1
Hooded Warbler 1
Canada Warbler 1
Summer Tanager 1
Scarlet Tanager 5
Northern Cardinal 2
Indigo Bunting 1

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