ITHACA, N.Y. — A study by the Cornell Lab of Ornithology finds many bird species have the bacteria responsible for house finch eye disease, but most don't show signs of illness.
Ornithologist André Dhondt says the bacterial parasite was previously thought to infect only a few species of feeder birds. But a study published in the online journal PLOS ONE shows it infects more than half the species tested, even ones that don't come to bird feeders.
Dhont says everyone has always assumed that feeders play a major role in the transmission of the disease, but the new study shows that's not necessarily so.
House Finch eye disease first appeared in North America in 1994 when people watching backyard feeders started seeing birds with swollen, runny eyes.