>I have found it interesting how far off
>people often are when they guess the weight of large birds like redtails or
>eagles. Today I noticed an article in the P.I about the snowies that said
>they weighed 8 pounds, which is heavier than I would estimate-- but I've
>never held one and when I looked in several guides, the Birder's Handbook,
>and the Encyclopedia Britannica I was frustrated to see that none of them
>gave the weight-- so I guess I won't know until Dennis corrects me.
>
>Name: Jerry Broadus

One set of weights given in the Snowy Owl account in Birds of North America
(perhaps these are available at Flora and Fauna Books), based on 20+
healthy birds of each sex in winter, gives mean weights for males of 1806
grams, females 2279 grams. At 454 g/lb., that's just 4 pounds for the
males, 5 pounds for the females. That article in the P.I. was full of
conventional (folk?) wisdom, not much of it proven and some of it probably
false, about Snowy Owls. Interestingly, the people quoted in the article
work at the same place as David Parmelee, the person who wrote the account
in BNA, but I guess he wasn't available.

I'll include one quote from Parmelee: "Many Snowy Owls that move southward
from arctic regions are mistakenly assumed to die from starvation.
Although this may prove to be the case during irruptive migrations of young
in western and eastern sections of North America, there is no evidence that
this is so in the N. Great Plains. In Alberta, 45% of the specimens
examined had moderate to heavy fat deposits, and traumatic injuries [mostly
human-caused] were the major sources of mortality. . . . .Only 14.1% was
believed due to starvation."

I would say at this time that there is also no evidence to indicate that
most of the owls we are seeing here will die of starvation. During our
last monster invasion, 73-74, dozens and dozens if not hundreds and
hundreds of Snowies spent much of the winter in this area, still fairly
common into March. Then they probably went home. Furthermore, Parmelee's
account does *not* provide any evidence for the long-touted hypothesis that
Snowy Owls irrupt when their prey (lemmings, voles) populations crash. In
fact, most evidence supports a mosaic of lemming population cycles on a
scale much too small to explain the large-scale irruptive behavior shown by
the owls. Parmelee concludes that we don't really have a clue why this
happens.

"Conventional wisdom" is too conventional for me.

Dennis Paulson, Director phone 206-756-3798
Slater Museum of Natural History fax 206-756-3352
University of Puget Sound e-mail dpaulson at ups.edu
Tacoma, WA 98416
web site: http://www.ups.edu/biology/museum/museum.html