Monday, November 19, 2007

Avian Pox, Squirrel Copulation, and Jay Food Stashing

Yesterday a male House Finch appeared at the feeder with what appears to be Avian Pox infecting the rear toe on his right foot.

The segmentation of the toe is visible though grossly swollen and the lesion is becoming rough and warty. This looks like the pox I've seen that infected a pigeon's foot. I caught the bird and the progression of the disease was that of Pigeon Pox. The lesion healed and after recuperation the bird was released healthy.
Therefore I'm making a presumptive diagnosis for this bird of Avian Pox.

Avian Pox is caused by an avipoxvirus. It's a slow developing disease that can be so mild as to be barely noticeable or severe enough to cause death. There are any number of strains of varying virulence and some strains are species specific. Previously when fewer strains had mutated or had been noticed at any rate, Avian Pox was broken down into three basic kinds: Pigeon Pox, Fowl Pox, and Canary Pox. (All birds that were kept by humans and therefore under closer scrutiny.) Eventually those pox were found to affect 60 avian species in 20 families. (Nope, humans don't get it. Okay, I haven't gotten it and no one else has gotten it either. It's an avian disease.) The species included everything from turkeys to occasionally raptors. Then in 1999, a flock of infected Black-capped Chickadees were noted in Europe. Though supposedly Avian Pox had been around forever, some people question this, it is considered an emerging avian illness in North America.
Though, possibly now as there are so many feeders, the birds are now close enough and observed often enough for the disease to be seen and tracked in wild birds.

At any rate sometime after the Chickadees, a new and in my opinion, better way to classify the disease came into play.

Now Avian Pox is only broken down into two types, cutaneous (dry)--like the finch above, and diphtheritic (wet).

Avian Pox lesions, eventually look rather warty, and affect the unfeathered areas of a bird's body.

If the lesion on the bird above, is the only infected area and it does not impede his ability to compete, the lesion will eventually open, drain, and scab over or shrink and dry out. If the bird avoids a bacterial infection in the open area, the spot will scar over and he'll go about his business good as new. Actually better than new as he will be immune to that strain of Avian Pox. Though if the lesion drains the detritus from that and the scabs are highly contagious. There is dispute about for how long, days to months, a surface or scab might remain infectious.
Some say warm humid weather is worse for pox. Other's say winter is worse. Basically there are any number of things that have not been utterly and categorically nailed down.

Mosquito's carry the pox for about 200 days after biting an infected bird and they pass the infection on when they bite later birds. A bird might also pick up pox by having a scratch that comes in contact with an infected surface or the virus on another bird. Or the Diptheritic form of the disease may be contracted by breathing the virus.

The Diptheritic form of Pox can be far more problematical as it can infect the mucus membranes, the mouth, the larynx, beak, and/or trachea. Beak integrity can be compromised particularly in Chipping Sparrows. Air flow can be cut off, eyesight obscured, or the ability to eat compromised either killing the bird outright or weakening it enough where it can't take care of itself.. Birds with this form often die.

And what does the Cornell Lab of Ornithology say?

"If a sick bird comes to your feeder, minimize the risk of infecting other birds by cleaning your feeder area thoroughly. If you see several diseased birds, take down all your feeders for at least a week to give the birds a chance to disperse. Remember that prevention is the key to avoiding the spread of disease. Regularly clean [my emphasis. D.B.] your feeders even when there are no signs of disease."

Follow the link for their recommendations on hygiene.

By the way, I do clean the surface of the patio very frequently. You just won't notice as the minute I finish and refill the feeders, the squirrels climb the screen or leap off the roof to the feeder and dump grand amounts on the patio looking for their favorites. No, I don't particularly attempt to fend off the squirrels. They have to eat too. Besides why make myself crazy?

A Black-capped Chickadee momentarily gets very near the infected Finch.

And now for something a least slightly more cheerful.

Here we have two young squirrels attempting to figure out how to copulate. First one would run up behind the other and try. Then the one previously on the bottom would run over and attempt to try from the top. They never did look to be successful but I'm sure they'll figure it out eventually. Notice Bottom is concentrating. She'll give it a try in a moment .

I do love the feather pattern on the back of a Blue Jay.
But this isn't about feathers, it's about my getting the binoculars on this Blue Jay as he sat on the telephone wire. When I focused in on him, I saw that he had a hefty kernel of field corn in his beak. I watched, he didn't swallow it. He just perched on the wire, scanned the area for a few moments, holding the corn right there near the tip of his beak. That's odd, I thought.

Then Blue Jay bounced down into the branches 10 feet from what I've taken to be an old squirrel's nest. Blue Jay looked at me. I retreated further into the shadows inside the house. He then bounced over to the leaves, his head went down, he then flew out of my sight line and then to the bath for a drink. Somewhere in there, he may have stashed his piece of corn. Drinking through corn wouldn't work all that well. Yes, he could have swallowed it.
Though he did look like he was up to something. Hmm. Besides the Blue Jay I've seen both a squirrel and a Crow take special interest in that spot. Was the Blue Jay periodically raiding another animal's stash, and caching the booty in a new spot?
I'll see if I can find out.
Donegal Browne

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