McGILL BIRD OBSERVATORY

FALL MIGRATION MONITORING PROGRAM

Unusual Black-capped Chickadee

The Black-capped Chickadee in the photos below was banded by Marcel Gahbauer at McGill Bird Observatory (Montreal, Quebec) on October 10, 2010.  Over 100 Black-capped Chickadees were banded that week, representing an unusually significant migration in this area.  This individual was immediately recognized as being different due to the brown outer greater coverts visible even with the wings closed. However, as photos below show, the tips of the primaries and secondaries are similarly faded to brown.  It appears this is likely a plumage abnormality rather than a matter of hybridism, but we welcome any thoughts about this bird by e-mail.  All photos by Marcel Gahbauer.


Seen from the side in sunlight, the brown in the greater coverts and primary coverts is visible.


In the shade the contrast is more subtle, but still apparent.


On the spread wing, it becomes apparent that there is a sharp contrast between the inner greater
coverts which have the normal gray appearance of Black-capped Chickadees, and the outer four
greater coverts that are brown.  The primary coverts are then again primarily gray and "normal",
but the alula is brown like the outer greater coverts.


A closeup of the coverts shows the contrasts better, and shows that the outer primary coverts may also be a bit pale.


With the wing partially closed, the contrast is even stronger.


Zooming in on the tips of the secondaries shows the fading to brown within the final centimetre or so.


Note the contrast between the brown wingtips and gray tail.

 

 

2002- The Migration Research Foundation Inc.