Easterly Winds Bring a Slow Day

Captain Sam's

The station has had a few slow days here. So, I’ve decided to write about one of our more interesting captures today — the Worm-eating Warbler. This bird forages in the dense understory of forests, often skulking on the ground and turning over leaves in search of caterpillars and other larvae. While in migration, a bird like this has a voracious appetite and at each stopover site it will attempt to gain as much fat as it can in preparation for its next long distance flight. Like many passerines in migration, the Worm-eating Warbler flies the greatest distances at night. There are numerous reasons for this. For example, it has been found that passerines migrate using the stars for guidance. That is a subject that deserves its own post.

Across both sites at the Kiawah Island Banding Station we have captured a total of 9 new Worm-eating Warblers thus far. The mass among these  birds has been between 10.7 and 19.5 grams. The heaviest birds had a fat score of 5, which is the highest score on our index and means that these individuals have practically doubled their typical weight in preparation for the journey south. We have yet to recapture any, an indicator that they are landing here as a stop-over site then moving on again the next evening. The precise wintering destination for each of these birds is unknown, but they will end up somewhere in the islands of the Caribbean or the lowland forest of Northern Central America.

-Vincent

 

Worm-eating Warbler - Photo: Vincent Weber

Citation: Vitz, A. C., L. A. Hanners, and S. R. Patton (2020). Worm-eating Warbler (Helmitheros vermivorum), version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.

Little Bear: 

Though we had a mostly slow day at Little Bear before closing early due to an approaching thunderstorm, there was one big excitement: another Chuck-will's-widow! Like our previous capture, this bird was also a hatch-year. 

Hatch-year Chuck-will's-widow. Check out the rictal bristles around the mouth for catching insects! (Photo: SS)

Another notable capture was a hatch-year male Downy Woodpecker. Woodpeckers are interesting and sometimes difficult to age because of their complicated molt strategies. However, this means that we can often age them through their third year of life (compared to only 2 years for most birds!) The primary coverts are often one of the most useful clues. They are retained in a hatch-year bird, so are uniformly brownish, whereas in a second-year bird only the outer primary coverts are replaced and contrast with the browner inner coverts. In an after-second-year bird, the primary coverts will be uniformly adult or mixed with fresh and retained adult feathers. On our bird, the primary coverts (outlined red in the photo) are uniformly brown and contrasting with the darker greater coverts (green). Also, the bird's last primary (p10) is brown - a juvenile feather that hasn't been molted yet. And finally, we knew he was a male because of the red patch on the back of his head.

Hatch-year male Downy Woodpecker (Photo: SS)

Thunderstorms are predicted for tomorrow morning, so we'll have to wait and see if we'll be able to band...

- Sarah M.

 

Species	Captain Sam's		Little Bear
	New	Recaps	New	Recaps
Chuck-will's-widow	-	-	1	-
Downy Woodpecker	-	-	1	-
White-eyed Vireo	1	-	-	1
Red-eyed Vireo	3	1	-	-
Carolina Wren	-	-	-	2
Worm-eating Warbler	1	-	-	-
Northern Waterthrush	1	-	2	-
Common Yellowthroat	5	-	2	2
American Redstart	1	-	1	-
Yellow Warbler	2	-	-	-
Northern Cardinal	-	2	-	-
Painted Bunting	4	3	6	3

Today's Banding Stats	Captain Sam's	Little Bear	TOTAL
# Birds Banded	19	13	32
# of Recaptures	6	8	14
# of Species	8	9	11
Effort (net-hours)	149.2	104.5	253.7
Capture Rate (birds/100 net-hours)	15.4	33.5	49.2
# of Nets	30	22	-

2020 Fall Cumulative Banding Stats	Captain Sam's	Little Bear	TOTAL
# Birds Banded	632	357	989
# of Recaptures	214	57	271
# of Species	33	32	42
Effort (net-hours)	2899.31	1322.85	4222.16
Capture Rate (birds/100 net-hours)	28.9	29.7	29.8
# of Days	24	16	-

Banding Staff
Kristin Attinger (CS)
Dan Errichetti (CS)

Vincent Weber (CS) 
Josh Lefever (LB)

Sarah Mueller (LB)
Sarah Stewart (LB)