Songbirds at Higher Risk of Eye Disease From Backyard Bird Feeders

Are we making our feathered friends sick? A recent Virginia Tech study has found that bird feeders are linked to a common eye disease that songbirds are susceptible to and that is spreading increasingly.

"Our results suggest that in this species, a few individuals -- those that like eating at feeders -- are likely very important in driving disease epidemics," Dana Hawley, a member of the Global Change Center at Virginia Tech, said in a news release. "If this is true for other wildlife species as well, we may be able to more effectively reduce disease by targeting these 'high risk individuals."

For their study researchers examined common backyard songbirds known as house finches that are susceptible to contracting a bird disease called Mycoplasmal conjunctivitis in the same way that humans contract "pink eye." Infected birds generally display red, swollen eyes that often leads to blidnenss or death from not being able to see to navigate, search for food or even protect themselves.

Synchronized chips with barcodes were attached to the birds and registered which birds visited bird feeders and when they tended to make their visits which helped researchers analyze feeding patterns and social networks.

"This technology enabled us to capture where birds fed during the winter and who they chose to feed with," Sahnzi Moyers, a doctoral student who works with Hawley, said in the release.

Like children catching the chickenpox from their friends at school, the birds that fed with a lot of other birds were at a higher risk of catching the disease and spreading it to their social circle.

"We expected birds that were more central in the social network, or had more friends, to catch the disease, because previous research has found that this was important for accessing information about where food is located. But, we found instead that it was birds' feeding preferences that were most important," Damien Farine, co-author and a postdoctoral researcher with a joint appointment at the University of Oxford and the University of California-Davis, said in a statement.

The researchers noted that understanding the spread of this infectious eye disease can aid in conservation efforts. While bird feeders play a key role in songbird survival during winter months, people can do their part in keeping the birds they invite for a meal healthy by disinfecting feeders before refilling.

 Their findings were recently published in the journal Proceedings of the Royal Society B. 

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