Birds of a feather don’t share a sick bed

House finches avoid sick members of their own species, say scientists, in a finding that could be useful for tracking the spread of diseases like bird flu that also affects humans.

Laboratory tests showed that the house finch, a particularly social North American species (Carpodacus mexicanus), was able to tell the difference between sick and healthy fellow birds and tended to avoid those that were unwell.

This was the first time that avoidance of sick individuals, already observed in lobsters and bullfrog tadpoles, has been shown in birds, according to a paper published in the journal Biology Letters.

"In addition, we found variation in the immune response of house finches, which means that they vary in their ability to fight off infections," says co-author Maxine Zylberberg of the California Academy of Sciences.

"As it turns out, individuals who have weaker immune responses and therefore are less able to fight off infections, are the ones who most avoid interacting with sick individuals."

This all meant that there were differences between individual birds’ susceptibility to disease, the time it would take them to recuperate and their likeliness to pass on the disease.

"These are key factors that help to determine if and when an infectious disease will spread through a group of birds," says Zylberg - and how quickly.

(Image credit)