About us: We own the Wild Birds Unlimited nature shop in East Lansing, Michigan,
a store that provides a wide variety of supplies to help you enjoy the birdwatching hobby.

This blog was created to answer frequently asked questions & to share nature stories and photographs.
To contribute, email me at bloubird@gmail.com.

Wednesday, August 4, 2010

Why Are There Dead Birds Under My Feeder?

Hello, We've had an odd situation this summer regarding our birds. We have several backyard feeders which are very busy all year 'round. This spring and summer, however, I have, on five separate occasions, found a dead bird lying in the same spot in front of one of our feeders. The first was a robin, then a sparrow, and then several red-winged blackbirds. The birds don't show any signs of trauma - and it doesn't look like any other animal has tried to eat any of them. I'm trying to figure out what might be causing this.

I know we sometimes have a stray cat or two roam through the yard, but I would think that a cat would eat at least some of any bird it might catch. I've also considered that the birds might be finding something to poison them. I would think, though, that if poison were the case, more than five birds would have run into it over the course of three or four months.

Any ideas?? Thanks, Jan

I don’t suspect West Nile Virus. The first birds to be affected by that are Blue Jays, Crows and Ravens. For more information go to the Michigan DNR website on How to Report a Dead or Sick Bird or Mammal from Michigan.

It doesn’t sound like the deaths at feeders can be attributed to salmonella either. Salmonellosis can be found in finches late winter and early spring when overcrowding, dirty feeding areas and a stressed immune systems, increase the risk to birds at feeders. For more information go to Michigan DNR Salmonella.
However it’s always a good idea to make sure your feeders are cleaned at least once a month with a vinegar solution or Scoot. Read more about cleaning your feeders from a previous blog post: Important Backyard Birding Tips
I suspect that the variety of dead birds found around your feeder is the result of a cat. There are more than 90 million pet cats in the U.S., the majority of which roam outside at least part of the time. This is not good news if you are a bird!
Even well-fed cats kill birds and other wildlife because the hunting instinct is independent of the urge to eat. These cats usually “play” with the bird until it stops moving and then leave the bird behind without any visible trauma.

The following is an abstract of a paper, written by Michigan State University researchers: “To understand the impacts of cat predation on birds, we surveyed all 1694 private landowners living on three breeding bird survey (BBS) routes (~120 km) that represent a continuum of rural-to-urban landscapes in Southeastern Michigan, where the majority (>90%) of land is privately owned. Across the three landscapes there were ~800 to ~3100 cats, which kill between ~16,000 and ~47,000 birds during the breeding season, resulting in a minimum of ~1 bird killed/km/day. Our results, even taken conservatively, indicate that cat predation most likely plays an important role in fluctuations of bird populations and should receive more attention in wildlife conservation and landscape studies.”
Source: Landowners and cat predation across rural-to-urban landscapesBiological Conservation, Volume 115, Issue 2, February 2004, Pages 191-201Christopher A. Lepczyk, Angela G. Mertig, Jianguo Liu
Cats Indoors logoImage via WikipediaThe American Bird Conservancy has developed a campaign – called Cats Indoors! – to educate cat owners about the damage their pets can do to songbirds, other wildlife and themselves by freely roaming the outdoors.
For more information, visit http://www.abcbirds.org/abcprograms/policy/cats/
Thanks VERY much!! This helps solve the mystery. Jan
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Anonymous said...

My friend has had a bunch of Red Poles at his and his parents feeders this Winter in Pennsylvania but they have found 10-12 of them dead. No visible injuries and no other species have been found dead. This is the first time he has ever had Red poles. Do you have any idea what could be causing this?


Wild Birds Unlimited Mid-Michigan said...

I’m not surprised it was the first time he had redpolls in a while. I wrote earlier about how this was going to be a good season for bird watching because Canada’s natural seed crops were horrible this year and lots of birds that usually like to winter further north had to have venture south to states like Michigan and Pennsylvania to find food.

Because of this increased traffic it is very important to keep your feeders clean. These flocks of birds are going to be stressed and susceptible to disease. Feeders should be cleaned at least once a month, year round. Disassemble feeders and immerse them completely for three minutes in a mild one part vinegar to nine parts water solution. Scrub with brushes, rinse thoroughly, and let air dry.

However, at the end of winter, if people find dead birds around their feeder or lethargic birds huddled close to houses it may mean a Salmonellosis outbreak. Signs range from sudden death to gradual onset of depression over 1 to 3 days, accompanied by huddling of the birds, fluffed-up feathers, unsteadiness, shivering, loss of appetite, and rapid loss of weight. Especially susceptible to Salmonellosis during these stressed times are House sparrows, Pine Siskins, American Goldfinches, and Common Redpolls.

No drugs or antibiotics have proven to be entirely effective for treating salmonellosis in any wild birds. At the site where there are die-offs, feeders should be disinfected weekly to help reduce transmission and the area underneath should be raked clean as well.

Salmonellosis refers to disease caused by bacteria in the genus Salmonella. How outbreaks begin is not known. Possibly some birds are carriers of the disease and either spread it or become affected themselves when stressed.

So in order to keep healthy birds at your feeders:

1. Feeders should be cleaned at least once a month, year round. And weekly if you see any sick birds. You can purchase professional cleaners like Scoot at Wild Birds Unlimited, or use a mild one part vinegar to nine parts water solution to disinfect all of your feeders. Disassemble feeders and immerse them completely for three minutes. Scrub with brushes, rinse thoroughly, and let air dry.
2. Check your feeders after a rain and snow to make sure the seed is dry. If not, replace it.
3. Store seed in a cool dry location.
4. When choosing a new feeder look for something easy to clean and fill.

If you keep these measures in mind, you can keep this hobby enjoyable for your family and safe for your birds.