iSeeChange: Dead Finches

Aug 14, 2015

A house finch at a feeder.
Credit Flickr User quinet

Earlier this summer, we received an observation over at iseechange.org about finches.  Ann Cabillot  had a mystery: dead purple finches found across Paonia.

“About a couple months ago, I started noticing sick birds.  They looked really lethargic.  They had no fear of me, they’d just be sitting there when I walk a foot away,” said Anne.

She began asking her friends if they had noticed the same thing. 

“One person said ‘Oh yeah, I found one dead on Second Street.  I was walking with someone in the park, and right on the path, there was another one,” she said, “another dead purple finch."

“And then one day, I was watching one outside my window,” she said, “and I got my binoculars, and it was hopping a little bit, and it had flies around its head.  It was trying to shake them off.  Within 45 minutes – an hour, it was dead.”

She’s been a lifelong bird lover, and a lifelong bird feeder, admiring them through her back window.  She’s heard stories of people who were not quite as fond, and would set out poisoned bird feed to keep black birds away from livestock feed.

“What exactly is killing them?” said Ann.  “Is it a disease, or has somebody been putting out poison bird food to kill the black birds?”

Nathan Seward is a researcher with Colorado Parks and Wildlife.  Anne sent one of the birds she found, frozen, to CPW, and they ran some tests to find out what killed the bird. 

“We have documented salmonellosis,” said Seward.  “It’s a general disease caused by the bacteria salmonella.”

It’s pretty much the same issue that someone might run into with poultry.  The bird was also likely a house finch, easily mistaken for a purple finch, but the fact remains: it’s dead.  It turns out that what’s killing these finches isn’t so much malevolent as it is gross.

“The Salmonella bacteria, it gets spread throughout the body of the infected bird, and what normally happens is it causes diarrhea,” he said.  “The infected feces then gets spread from bird feeder to bird feeder, and also in the droppings underneath the bird feeders.  As other birds come into feed, they also get infected with the bacteria.”

This is a pretty natural disease to affect birds in Colorado.  However, Anne was noticing a lot of them dying, this year in particular.  It might be natural, but there may be a reason this population on the Western Slope has been hit hard this year.

“Well, the increased moisture we’ve seen this year definitely may have exacerbated the development of the salmonella bacteria in the bird seed in the ground, in the fecal droppings,” said Seward.  “That moisture helps facilitate development of that bacteria.”

Seward recommends that anyone who feeds birds regularly clean the feeders in a bleach bath, but to be sure to take precautions: salmonella is a nasty disease in humans too.  He also recommends making sure bird feeders are perched up high, to keep away something else that’s dangerous to humans: bears. 

If you’ve noticed anything different about the natural world, if you have any questions about what’s going on out there, let us know, at iseechange.org.