Subject: Pine Siskin Virus?
Date: Feb 3 07:48:49 2004
From: David Lyles - oregondave at hevanet.com


At 4:45 AM -0800 2/3/04, Susan Carmel wrote:

>Tweeters,
> I heard, from a friend who volunteers at PAWS, that there is a
>contagious illness affecting Pine Siskin . Apparently they are
>suggesting that people either clean their birdfeeders daily, or
>just take them down to help prevent this illness from spreading
>further. Maybe I wasn't paying attention, but I haven't found this
>news on Tweeters (though I remember someone recently reporting dead
>Pine Siskin at a feeder site). Can anyone confirm this info?
>Susan Carmel
>Seattle

Susan,

Here's one posting from 2001 on the subject. A search of the archives
should turn up more discussion on the efficacy of cleaning feeders.

David Lyles
Portland OR
mailto:oregondave at hevanet.com

>Date: Fri, 16 Mar 2001 03:04:04 -0800
>
>From: Tom Besser <tbesser at vetmed.wsu.edu>
>To: "'tweeters at u.washington.edu'" <tweeters at u.washington.edu>
>Subject: Siskin salmonellosis
>
>Tweeters:
>
>I'm a diagnostic microbiologist and I find Siskin salmonellosis a
>very interesting problem though I certainly don't have any
>solutions. There is a literature on the subject, and it confirms
>that Pine Siskins are the most susceptible finch species in the US.
>Siskin salmonella die-offs have been recognized around the country
>as an almost annual event.
>
>Last year, I solicited samples from dead Siskins from Tweeters and
>others who have seen feeder death birds (and of course I've seen the
>problem at my own feeders as well). In 1999, the salmonella isolates
>from Siskins (and a few Grosbeaks, Goldfinches and House Finches)
>from Montana to Puget Sound, and from the Canadian border to
>southern Oregon were all a single identical 'fingerprint' strain of
><Salmonella typhimurium>, and that strain as not found at all among
>several hundred human and animal <S. typhimurium> isolates from that
>year. This suggested that Siskins were carrying a unique salmonella
>around with them. (I also tested birdseed samples from many
>Tweeters, to see whether the salmonella could have originated and
>been spread around with thistle or sunflower seeds, but all have
>tested negative, suggesting that this is not the source of the
>problem.)
>
>If Siskin salmonellosis follows the same patterns as salmonellosis
>in other animals, it's very likely that any concentration of the
>birds will contain one or more carrying this strain in its
>intestines, probably with no apparent illness. Any persistent
>concentrations of birds (read, feeder stations) are likely places
>where the comtamination will become heavy enough to cause sickness,
>and sick birds will shed much higher levels of the bacterium,
>leading to more sick birds.
>
>If that is the case, Dennis is absolutely right that disinfecting
>feeders will have no practical beneficial effect. The contamination
>is not just on the feeder, it's probably in the birds themselves and
>it's certainly in the ground around the feeders where the birds also
>spend a lot of time foraging. No disinfection (other than drying and
>sunshine and time, hard to find in the PNW springtime) can
>effectively disinfect the ground.
>
>The best solution seems to me to be to disperse the birds, by
>stopping feeding for a while. It's hard to say whether this will
>actually have much of a positive effect: it could be that flocks in
>urban and suburban areas will just head to the neighbor's feeder
>where the same problem will persist. (In fact, it's possible that
>the same problem could be occurring in Siskin flocks that never
>visit feeders: a lot of Siskins could die in the woods without being
>noticed.) Still, I think stopping feeding when you find dead Siskins
>is sensible, and more likely to have a beneficial effect than
>disinfecting feeders.
>
>Last, despite the fact that the Siskin salmonella strain hasn't
>appeared in human cases in Washington, it undoubtedly has the
>potential to infect you and make you (or more likely, your children)
>very unpleasantly sick: Don't forget to wash your hands very
>carefully with hot soapy water after touching your feeder or a dead
>bird.
>
>Tom Besser
>Moscow ID
>tbesser at vetmed.wsu.edu
>
>by way of Edinburgh Scotland
>(where 'feeder table' salmonellosis is also a problem)