Frequently asked questions (en anglais)
Nous nous excusons, mais cette page n’est présentement pas disponible en français
Seen a sick bird and want to report it?
Participants in Project FeederWatch can provide their observations of diseased House Finches in their standard count entry procedure. It is especially important for people to report if they look for the disease but don’t see house finches with apparent infection. This means checking the “yes” box when asked if you looked for the infection, and typing in a “0” when asked how many finches were infected. You may think zeros are boring, but they are not! In order to track the spread of any disease, we need to know where is occurs, but also where it does not yet occur.
What does conjunctivitis look like?
Infected birds have red, swollen, runny, or crusty eyes; in extreme cases the eyes become swollen shut or crusted over, and the birds become essentially blind. Birds in this condition obviously have trouble feeding. You might see them staying on the ground, under the feeder, trying to find seeds. If the infected bird dies, it is usually not from the conjunctivitis itself, but rather from starvation, exposure, or predation as a result of not being able to see.
Do other diseases cause similar clinical signs?
Avian pox is another common disease that affects a bird’s eyes. This disease causes warty lesions on the head, legs, and feet, but cannot always be easily distinguished from conjunctivitis. Avian pox is transmitted by biting insects, by direct contact with infected birds or contaminated surfaces (e.g. feeders), or by ingestion of contaminated food or water. Just as with conjunctivitis, the infected bird becomes vulnerable to predation, starvation, or exposure.
What causes the conjunctivitis?
Although infected birds have swollen eyes, the disease is primarily a respiratory infection. It is caused by a unique strain of the bacterium, Mycoplasma gallisepticum, which is a common pathogen in domestic turkeys and chickens. The infection poses no known health threat to humans, and had not been reported in songbirds prior to this outbreak. Researchers at various institutions are currently trying to learn more about the transmission, genetics, and development of this disease.
Where did the disease start? How far has it spread?
Conjunctivitis was first noticed in House Finches during the winter of 1993-94 in Virginia and Maryland. The disease later spread to states along the East Coast, and has now been reported throughout most of eastern North America, as far north as Quebec, Canada, as far south as Florida, and as far west as California. It has also appeared in some species other than House Finches. Your participation in Project FeederWatch will help document further changes of this epidemic.
What other bird species have been diagnosed with Mycoplasmal conjunctivitis?
So far, the disease is most prominent in the House Finches. However, a few reports of the disease have been confirmed in American Goldfinches, Purple Finches, Evening Grosbeaks, and Pine Grosbeaks, all members of the family Fringillidae.
Why might eastern House Finches have been the earliest victims of the disease?
House Finches are not native to eastern North America. Until the 1940s, House Finches were found only in western North America. Some birds were released to the wild in the East after pet stores stopped illegal sales of “Hollywood Finches,” as they were commonly known to the pet bird trade. The released birds successfully bred in the wild and spread rapidly throughout eastern North America. Because today’s eastern House Finch populations originated entirely from a small number of released birds, they are highly inbred, exhibit low genetic diversity and, may therefore be more susceptible to disease than other bird species native to the East.
Why has the disease spread so rapidly among House Finches?
The House Finch population is large, and the birds tend to move together in highly mobile foraging flocks. Therefore, diseased individuals are constantly entering new areas, increasing the chance of infecting other birds in that area. Also, some infected birds do not die from the disease, which increases the probability of its transmission to other individuals. Lastly, current evidence suggests that infected birds do not acquire immunity to future infections.
Do bird feeders encourage the spread of conjunctivitis?
Whenever birds are concentrated in a small area, the risk of a disease spreading within that population increases. Even so, feeding birds may not necessarily increase the rate of disease spread, and should not have a net negative impact on the House Finch population. House Finch Disease Survey data tell us that the disease has decreased from epidemic proportions and is now restricted to a smaller percentage of the population. We estimate that 5% to 10% of the eastern House Finch population has this disease and that the dramatic spread that occurred a few years ago has equilibrated. This means that it is still an important and harmful disease, but that House Finch populations are not currently at extreme risk of wide-spread population declines.
Nonetheless, please be responsible and clean your feeders on a regular basis even when there are no signs of disease.
What should I do if I see a bird with conjunctivitis?
Take down your feeders and clean them with a 10% bleach solution (1 part bleach and 9 parts water). Let them dry completely and then re-hang them. Also, rake underneath the feeder to remove old seed and bird droppings.
Should I try to treat an infected bird?
By law, only licensed professionals are authorized to handle most wild birds. Although it is possible to treat finches with conjunctivitis, you should not add medications to bird seed or baths under any circumstances. There is no way to know if medication actually helps birds in uncontrolled conditions, and such treatment may in fact contribute to disease spread by allowing infected birds to survive longer. Treatment with antibiotics may also lead to the rapid evolution of novel strains of the disease that could possibly spread to other songbirds.
Bird-Feeding Guidelines:
Space your feeders widely to discourage crowding.
Clean your feeders on a regular basis with a 10% bleach solution (1 part bleach and 9 parts water) and be sure to remove any build-ups of dirt around the food openings. Allow your feeders to dry completely before rehanging them.
Rake the area underneath your feeder to remove droppings and old, moldy seed.
If you see one or two diseased birds, take your feeder down and clean it with a 10% bleach solution.