February 8th – Disease and Debilitation

Plumage of an ASY-M American Goldfinch

It’s commonly thought that disease, injury and old age are synonomous with imminent death in wild bird populations. A corollary of this is that disease is associated with old age. This isn’t necessarily the case as we found out today. We caught two male American Goldfinches that would be considered “aging” (if not old) in bird terms but in great shape; a young male American Goldfinch with the bad eye disease, Mycoplasmal conjunctivitis; a Black-capped Chickadee that appears to be blind in the right eye but still getting by; and “old Stumpy”, who appears to be thriving.

Wing features of the ASY-M AMGO - note the bright yellow epaulettes.

The two older goldfinches were both retraps. One we banded in 2008, recaught it in 2009 and hadn’t seen it since. The other was banded in 2009 but not seen since. Both birds were quite heavy, carrying a good fat load.

Mycoplasmal conjunctivitis in a young male American Goldfinch.

The young goldfinch with conjunctivitis had a completely closed swollen right eye. Despite its looks, it was heavy and carrying fat. We look forward to perhaps re-catching this bird in the future and finding it has lived through the disease (as we found with a House Finch one year).

The "milky" right eye of this Black-capped Chickadee probably indicates blindness on that side.

The chickadee was originally banded in the Fall of 2011 as a young bird. A “milky” right eye was noted at that time and in subsequent recaptures. The bird does not seem to be debilitated with reduced vision as it was well-muscled and had a normal weight.

One-legged "Stumpy" continues to thrive.

This about the 5th time we’ve recaught “Stumpy” – banded originally in the Fall of 2011 as a young bird. At the time of this capture (s)he weighed 11.9 g, which is just under the highest weight of 12.0 g recorded for it. So Stumpy is continuing to do well.

On another note, I would like to direct you to Peter Thoem’s excellent blog, My Bird Of The Day. He includes excellent descriptions and, often, pictures of birds he’s seeing.

Banded 11:
2 American Tree Sparrows
9 American Goldfinches

Retrapped 16:
1 Eastern Tufted Titmouse (there were at least 5 around)
4 Black-capped Chickadees
3 American Tree Sparrows (2 of them returnees from last Winter)
4 Dark-eyed Juncos
4 American Goldfinches


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