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Axel Hildebrandt
01-01-2009, 10:08 PM
Interesting explanation for the high number of snowy owls migrating. Did you know that one adult pair raises up to 13 young birds in one breeding season?

http://www.democratandchronicle.com/apps/pbcs.dll/article?AID=2008812310312

Eleanor Kee Wellman
01-04-2009, 10:32 AM
Thanks for posting, Axel! Interesting that the picture with the article shows Tom McDonald holding two Snowy Owls. In the field I would think that the one on the left is a female because the markings are so dark. Although the caption does not indicate the sex of the two birds the article states that he catches mostly juvenile males.

I would appreciate hearing comments about sexing Snowy Owls in the field.

Eleanor Kee Wellman
01-04-2009, 10:39 AM
This article ends up saying that the reason for Snowy Owl movement is lack of prey. It comes about by overfeeding, though, rather than a lemming crash. It is thought that this was the reason for the huge influx of Great Gray Owls a few years ago.

Dr. James Duncan, Manitoba Conservation, said that the great grays had two very successful breeding years before the juveniles moved south. Dr. Duncan has been studying these owls for more than 25 years.

Axel Hildebrandt
01-04-2009, 10:40 AM
I find it quite difficult to distinguish juvenile male and female birds. This is a quote from the Cornell "All About Birds" website:

Young male Snowy Owls are barred with dark brown and get whiter as they get older. Females keep some dark markings throughout their lives. Young males tend to have a white bib, a white back of the head, and fewer rows of bars on the tail than females. Although the darkest males and the palest females are nearly alike in color, the whitest birds are always males and the most heavily barred ones are always females. Some old males can be nearly pure white.