Monday, November 4, 2013

New Species: Ash-throated Flycatcher!

Strong northeast winds severely handicapped our effort today but, despite that, we still banded 45 new birds and had 10 recaptures of 11 different species.  The biggest surprise of the day came around 8:00am when we came upon a Myiarchus flycatcher in net #5.  Wow!  A really late Great-Crested Flycatcher, I thought at first . . . until I noticed the extremely pale yellow belly.  Then, that really got me thinking.  After several measurements and a careful study of the bird's plumage, we came to the conclusion that what we had was an ASH-THROATED FLYCATCHER!  Not only was this the first banding record for this species at KIBS, it also represent the 3rd record for the State of South Carolina.  The first was found in 1976 in Williamsburg County.  The study skin now resides in the Charleston Museum.  The 2nd was discovered and photographed in 2011 at the Savannah Spoil Site in Jasper County, SC.  

Ash-throated Flycatcher (HY, sex unknown)
The following series of photos show the unique characteristics that we used to identify this bird as an Ash-throated Flycatcher.  In addition those characteristics, a couple of measurements were also taken that helped to solidify the identification:
                 1.  Bill width at the nares
                 2.  The length of p10 minus the length of p4

The bill width at the nares was 6.9 mm which is smaller than the range for both Great Crested Flycatcher (7.4-9.2 mm) and Brown-crested Flycatcher (7.7-10.1 mm).

p10 minus p4 was -2.8 mm which means that the 4th primary feather was longer than the 10th primary feather.  In both, Great Crested (2-9 mm) and Brown-crested (0-8 mm) that number will be greater than or equal to zero. 

Note the light yellow wash of the belly, flanks, and undertail coverts.  In Great Crested Flycatchers, the yellow would be much brighter. 

The brown coloration of the rectrices wraps around the tip of the feather.  In all other Myiarchus flycatchers, the brown will not wrap around to the tip of the feather.

Another look at the brown tipped rectrices.

Entirely dark lower mandible.  Great Crested Flycatcher will have a yellow-orange base to the lower mandible. 

Mouth-lining flesh colored in Ash-throated.  Mouth lining yellow-orange in Great Crested. 
- Aaron   

1 Common Ground-Dove
1 Ash-throated Flycatcher
2 Ruby-crowned Kinglet
1 Hermit Thrush
2 Gray Catbird
32 Yellow-rumped Warbler (Myrtle)
1 Eastern Towhee
3 Song Sparrow
2 Swamp Sparrow

2 Common Ground-Dove
1 Carolina Chickadee
1 Ruby-crowned Kinglet
1 Hermit Thrush
4 Gray Catbird
1 Northern Cardinal

# of Birds Banded:  45
# of Recaptures:  10
# of Species:  11
Effort:  88.7 net-hours
Capture Rate:  62.0 birds/100 net-hours
# of Nets:  20 (but 5 nets were closed early due to wind)

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