Wednesday, October 10, 2012

Confusing Fall Warblers

What happens when you take two decent birders, a yard with regular MacGillivray's Warblers, some bright evening light, and a "Mac" in size and behavior that has no gray on the throat?

7 pm - Something in the giant mallow - very brown back... Wow, that's a BRIGHT MacGillivray's...! Wait, it's not a Mac... or do you see any gray on the throat? Look at those eye arcs... and the bicolored beak, that's too big for yellowthroat. Bright yellow vent and belly, must be a Mourning! *scrambling around kitchen window with bins and books while puppies whine about a late dinner*

[They walk dogs, return when light is fading and take photos. And then all ID chaos breaks loose.]

8-9 pm - this:

...but its vent was bright yellow? Why is the beak so thin and short and dark?

...the throat was so BRIGHT. Why is the belly faded?
The bill looks quite different from that first photo...
Why doesn't the bill appear bicolored? What happened to the YELLOW belly?

 ...and that is how bright light and a positive ID at 7 pm, followed by photos around 8 pm, turned a perfect-on-paper Mourning Warbler into a Common Yellowthroat. 


Could there have been two birds yesterday?  A bright yellow undersided and a duller one.  The one in the photos was far duller than the bright bird we watched.

This morning?  The duller bird, quite like the photos at times, still inhabited the area.

We did not see it this evening to compare its looks in bright light.

It is important we check ourselves from time to time; even those among the most confident.  In reality, perhaps most importantly among the confident.

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