For the Birds Radio Program: Bird Diseases
(Recording of a Scarlet Tanager)
No, that wasn’t a robin with a sore throat, though that is the best description of the song of the Scarlet Tanager. I’m just getting over a head cold which started me wondering whether birds ever get colds–I never see them hunting up Contac or Dristan at the drugstore, or bundled up, coughing delicately into bird hankies as they drink chicken soup.
Birds are immune from many human diseases. They have no appendix to develop appendicitis, no teeth to decay, no nose to run. No bird has ever developed tennis elbow, football players’ knee, or jock itch. Thrush, a fungus disease that human babies often get, is not found in real thrushes. Pigeons are supposed to have pigeon toes. Airsickness and seasickness are probably not problems in the bird world. And as far as I have been able to find, they don’t get the common cold.
But birds do get plenty of other sicknesses–like pneumonia and bronchitis. Unlike people, birds don’t get these from viral colds–they get them as side effects of a fungus disease called aspergillosis. A mold’s spores lodge in the bird’s lungs and air sacs, slowly but surely killing it. At least 48 species of birds, from Bald Eagles to songbirds, get it. In the beginning, the birds gasp and wheeze. Then they mope around for a while. But they don’t lose their appetites, and so they readily spread the disease at feeding stations before they die.
Once aspergillosis attacks a bird, there is no cure. But if you’d like to prevent the birds at your feeder from getting it in the first place, always set out clean seed. If it gets moldy, the mold is probably aspergillosis–dispose of it where birds can’t get to it. And keep your feeders clean–infected birds can spread the disease through their droppings.
Birds are also victims of bacterial diseases. Perhaps the worst is botulism–in a single Oregon lake in 1925, botulism killed a million birds, mostly waterfowl. In periodic outbreaks, hundreds of thousands of birds are killed by it–especially at places where large numbers of birds gather and feed for a long period of time. Botulism occasionally kills feeder birds, but the bacterium is mainly found in soil and water.
Parrot fever, properly called chlamydiosis, is another bacterial disease, and this one can be transmitted from birds to humans. It’s almost always found in captive birds, not wild ones.
Birds are hosts of viral disease organisms, too. They get encephalitis, quail bronchitis, Newcastle disease, and duck plague–all nasty diseases which probably don’t affect people at all. And though birds get bird pox, they apparently don’t get chicken pox.
Plenty of other bird diseases are caused by internal and external parasites. Birds develop cancers, heart diseases, and some other afflictions that plague humans. Avian metabolism is so fast that sick birds usually die much more quickly than sick people, and birds weakened by disease are often caught and eaten by predators before a disease can progress far. That may be why the life expectancy of a robin is only a year and two months, while the life expectancy of a person is about 70 years. Come to think of it, whatever it is in chicken soup must be a lot more beneficial to people than to chickens.
(Recording of a Scarlet Tanager)
This is Laura Erickson, and this program has been “For the Birds.”