Monday, September 23, 2013

Good Migration Last Night

We had a much better day today with 71 new birds and 10 recaptures of 17 different species.  There are still a lot of Common Yellowthroat moving through but we did have a nice variety other species including two new species for the season:  Ruby-crowned Kinglet and Swainson's Thrush.

An added bonus was a handsome adult male Chestnut-sided Warbler. We have only banded a few Chestnut-sideds over the years and this was our first adult male. He had an interesting plumage abnormality where he either retained or replaced the black cheek stripe but only on the right side.

Chestnut-sided Warbler (AHY, males)

I have wrote before about ageing warblers and other species using molt limits within the alulas feathers. Today we banded 5 Black-throated Blue Warblers of different age and sex classes. They are good examples to use to show this molt limit because of the very distinct contrast between replaced and unreplaced feathers.

Black-throated Blue Warbler (AHY, male)

Black-throated Blue Warbler (HY, male)


The first photo on the left shows an AHY male.  Notice that all 3 alulas are black and the edging on A1 and A2 are blue. 

The second photo shows a HY male.  This bird has replaced A1 but not A2 or A3.  Notice that A1 is black with blue edging but A2 is lighter with greenish edging.

Black-throated Blue Warbler (AHY, female)

The last photo is of an AHY female.  Females are not blue at all therefore they will have greenish edging to the alulas.  Notice that A1 and A2 have distinct green edging to them and all three alulas are dark. 

We did not get a HY female today but if we did A1 would would be dark with green edging while A2 would be lighter in color with little or no green edging.  


1 Common Ground-Dove
4 White-eye Vireo
3 Red-eyed Vireo
1 Ruby-crowned Kinglet
2 Swainson's Thrush
7 Gray Catbird
1 Brown Thrasher
1 Chestnut-sided Warbler
5 Black-throated Blue Warbler
6 Palm Warbler (Western)
1 Prairie Warbler
2 American Redstart
33 Common Yellowthroat
2 Northern Waterthrush
2 Painted Bunting

2 White-eyed Vireo
1 Red-eyed Vireo
1 Northern Mockingbird
1 Common Yellowthroat
4 Painted Bunting
1 Eastern Towhee

# of Birds Banded:  71
# of Recaptures:  10
# of Species:  17
Effort:  108.0 net-hours
Capture Rate:  75.0 birds/100 net hours
# of Nets:  20

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