[mou] Fwd: [wisb] Age and sex for Snowy Owls

[Jim Williams]

A good idea, worth sharing.
Jim Williams
Wayzata

Begin forwarded message:

From: "Cutright.Noel" <Noel.Cutright@we-energies.com>
Date: November 28, 2005 1:00:30 PM CST
To: "Wisconsin Birding Network" <wisbirdn@lawrence.edu>
Subject: [wisb] Age and sex for Snowy Owls

With the number of Snowy Owl observations being posted, I thought it
would be good if we could start noticing their plumage to determine age
and sex of these birds.  The following is from The Birds of North
America series; the SO account was prepared by Parmelee 1992.

Adult males are noticeably smaller and paler than adult females;
immatures most heavily marked as a rule.

Basic I plumage:  First-year males with white bib of 2-8 cm present and
back of head primarily white. First-year females with barring present in
all areas of plumage except for white facial disk, tarsi, feet and wing
linings; white bib, if present, less than 4 cm and back of head
primarily barred.  Females also show more rows of bars on underside (6
rows) and upperside (3 or more rows) of tail than do males (3 or fewer
rows).  Both sexes show moderate or extensive mottling on distal
portions of greater and/or median secondary coverts.

Basic II plumage:  not clearly defined, specimens examined showed mixed
characteristics of first-year and adult birds. (these are second year
birds)

Definitive Basic plumage: Plumage of adult males entirely white or white
except for narrow, sparse, pale gray, or brown barring on breast, back,
wings, head and.or tail.  Plumage of adult female with moderate ro
extensive barring present on breast, wings, head, and/or tail; little if
any mottling on distal portions of greater and/or median secondary
coverts; white bib of less than 8 cm present and/or back of head
primarily white.
The darkest males and the palest females are virtually alike in color,
but the whitest birds, sometimes practically pure white, are always
males, and the most heavily barred ones are always females.


Noel Cutright, Ozaukee County

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