Wednesday, September 30, 2015

Magnolia Impossible

Captain Sam's
We had a slow and humid morning today out at the "Spit". We banded 27 new birds and recaptured 10 of 8 species. The majority of birds banded were Gray Catbirds with 19 banded this morning. Our highlight bird was a hatch year Magnolia Warbler.

Magnolia Warblers are beautiful little birds that are notorious for being difficult to determine an individual's sex in the Fall for hatch year birds as well as for determining age and sex in the Spring for all birds. We're advised in our banding identification guide that with hatch year birds less than 5% should be sexed and since they can be difficult we will normally say our hatch year birds are of an unknown sex.

In the bird we caught today there are a few criteria that suggest this is probably a female bird. First, the green feathers on the back didn't have dusky or black centers and the streaking down the bird's flank was thin and indistinct. The amount of white in the tail is also considered an important plumage trait to sex Magnolia's, the white in the tail of the bird from today had a small amount of white on R2 (the most inside rect that will get white on it) and the amount of white reduces as it moves from the outer rects to the inner one. Males usually will get a very distinct white patch that is continuous and doesn't reduce as it moves to the inside rects.

For comparison, we've attached some pictures of an after hatch year male caught and banded last year, as well as a picture of a male Magnolia's tail.


Magnolia Warbler (Hatch year, unknown probable female)
Magnolia Warbler (hatch year, unknown probable female)

Male Magnolia Warbler, you can see the distinct streaking down the flank and black centers in the feather on the back
Male Magnolia Warbler tail, the amount of white remains continuous in male tail feathers whereas it gets much smaller in female Magnolias as it moves to the inside retrices

Little Bear
Today was relatively productive out at Little Bear, we caught 44 new birds and 9 recaptures for a total of 11 species. The species diversity was quite low with those numbers, we caught 20 Gray Catbirds and 18 Common Yellowthroats. The heat was quite brutal today and with the standing water left behind from the tides the past few days the humidity wasn't pleasant either. We are ready for this next cold front to change that along with bringing in some more diversity in our captures!

  Species Captain Sam's Little Bear
New Recaps New Recaps
Common Ground-dove -- 1 -
White-eyed Vireo- 1 - 1
Carolina Chickadee 1 - - -
House Wren -- 1 -
Carolina Wren- - - 1
Swainson's Thrush - - - 1
Gray Catbird 19 1 20 1
Magnolia Warbler 1 - - -
American Redstart - 1 - -
Northern Waterthrush - - 1 -
Eastern Towhee - - 1 -
Common Yellowthroat 3 4 18 5
Northern Cardinal 1 2 1 -
Painted Bunting 2 1 1 -

 Banding Stats Captain Sam's Little Bear TOTAL
# Birds Banded 27 44 71
# of Recaptures 10 9 19
# of Species 8 11 14
Effort (net-hours) 122.5 64.5 187
Capture Rate (birds/100 net-hours) 30.2 82.2 48.1
Nets 25 15 40

Banding Staff
Aaron Given (CS)
Mattie VandenBoom (CS)
Chris Snook (LB)
Nancy Raginski (CS)
Sean McElaney (LB)
Casey Weissburg (CS)
Micheal Gamble (CS)
Ryan Donnelly (LB)

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