May 2013 Two Buttes BT Green Warbler

[Steven Mlodinow]

Greetings All

Tony Leukering and I were reviewing photos for this spring's North American Birds' column and happened upon a surprise. 

Upon studying photos of this May's Two Buttes Black-throated Green Warbler, it became apparent the bird is actually a Black-throated Green x Townsend's Warbler hybrid. The range of these two species approximate each other closely in NE British Columbia and may (in reality) overlap. Features of this bird pointing towards hybrid are 

1) Yellow below black chest

2) Darker than normal cheek patch

3) Streaking on the undertail coverts

4) And more streaking than normal for Black-throated Green on back

I understand -- the bird had the typical black throat patten of a BT Green. When I saw that classic throat pattern, I didn't look much further... especially with GC Thrush, Philly Vireo, Cape May Warbler, Summer Tan, BTB Warbler and an abundance of other rarities in the vicinity. 

 A rather similar bird was seen on the Texas Coast in April 2011 and is widely considered to be a Townsend's x BT Green Warbler. The video can be seen at http://www.youtube.com/watch?v=9SLSsfB7GcI

Some have suggested that this cross may be more regular than thought. There have been two sightings of probable Townsend's x BTGN Warbler in CO previously, but without photographs. 

For an excellent photos displaying most of the above marks, go to:

http://www.pbase.com/gwalbek/image/150130138  

In any case, note that the Two Buttes bird will be considered a hybrid on eBird.... so feel free to change your list to such, but Black-throated Green Warbler will not be considered a valid ID for that bird. In reality, it was something far more marvelous... just wish that I'd realized it at the time.

Good Birding

Steve Mlodinow

Longmont, CO

[Brandon K. Percival]

There are photos of two Black-throated Green type Warblers (not just one) at Two Buttes Reservoir over that weekend.  One male and one female. 

Brandon Percival -- Pueblo West, CO

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From: Steven Mlodinow <sgm...@aol.com>
To: cob...@googlegroups.com
Sent: Sunday, November 10, 2013 3:45 PM
Subject: [cobirds] May 2013 Two Buttes BT Green Warbler

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[Steven Mlodinow]

Greetings All

All eBird reports pertain to the male as far as I could tell

Steve M

Sent from my iPhone