Sandy, Lynn, and others,

I would say that the illness you are seeing in Pine Siskins is
almost certainly salmonellosis, as Lynn suspects. I am attaching part
of a message to TWEETERS about siskins and salmonellosis that I sent
last November. Siskins seem to be especially vulnerable to
salmonellosis, although it can affect numerous other bird species as
well.

It is normal to see a small number of siskins affected by
salmonellosis in late winter and early spring every year. On rare
occasions, as described below, it can cause mass mortality, as it did
in 1992/1993.

Unfortunately, the mortality rate for siskins affected by
salmonellosis is high. There seems to be little one can do about it
other than periodically sterilizing bird feeders, changing seed
frequently, or even taking down feeders when sick birds are noticed.

The disease referred to by Blake Iverson, which is especially
common in House Finches, is avian pox, which is a compeletely
different illness from salmonellosis.

Wayne C. Weber
Kamloops, B.C.
wayne_weber at bc.sympatico.ca



> One subscriber wondered whether pesticides might be responsible
>for mortality of siskins. I am not aware of any major mortality
caused
>by pesticides, but there is at least one instance of mass mortality
>caused by Salmonella bacteria, probably associated with backyard bird
>feeders. Between November 1992 and January or February 1993, a major
>outbreak of salmonellosis occurred in Pine Siskins in southwestern
>B.C.
>(For details, see "The 1992-1993 Outbreak of Salmonellosis in Pine
>Siskins in British Columbia", by Victoria Bowes. British Columbia
>Birds, Volume 3, pages 13-14, 1993). Bowes documented a minimum
>mortality of 3100 Pine Siskins in southwestern B.C., and estimated
>that tens of thousands had succumbed. She also noted that similar
>die-offs had been reported at the same time in Washington, Idaho, and
>California.
> The die-off of Pine Siskins in 1992-1993 was massive, but for
some
>reason was virtually confined to the one species. Apparently, mass
>mortality of Pine Siskins on this scale has not been reported before
>or since this epidemic.