[CT Birds] Aging and sexing Snowy Owls

Don Crockett doncrockett63 at gmail.com
Sat Dec 14 20:14:57 EST 2013


I used http://www.newocr.com to do OCR on the png file.

I tried 2-3 other sites before finding this one that converted it
successfully. Did a great job. The only characters it failed to convert
correctly (that I noticed) were the "<=" signs. It missed some spaces and I
reformatted the " . . . " to make it more readable.

>From an article from the Journal of Field Ornithology, 1980 -
http://www.afonet.org/JFO/

SUMMARY

The following key for aging and sexing Snowy Owls was developed on the
basis of 33 owls
obtained from October through April:

la. Barring present on all areas of plumage except for white facial
disk, tarsi, feet, and wing linings . . . . . . . . . . . . . . . . . . .
FIRST-YEAR FEMALE

lb. Barring absent from parts of head or breast or other areas besides
facial disk,
tarsi, feet, and wing linings . . . . . . . . . . . . . . . . . . . . . . .
. . . . . 2

2a. Plumage entirely white or white except for narrow, sparse, pale gray or
brown barring on breast, back, wings, head, and/or tail . . . . . . . . . .
. . ADULT MALE

2b. Moderate or extensive barring present on breast, wings, head, and/or
tail . . . . . 8

3a. Moderate or extensive mottling present on distal portions of greater
and/or median
secondary coverts . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . 4

3b. Mottling absent from distal portions of greater and/or median secondary
coverts
or very slight mottling present . . . . . . . . . . . . . . . . . . . . . .
. . . . . 5

4a. White bib of 2-8 cm present and back of head primarily white . . . . .
FIRST-YEAR MALE

4b. White bib, if present, 54 cm and back of head primarily barred . . . .
. . . . FEMALE

5a. White bib of <= 8 cm present and/or back of head primarily white . . .
. . . . FEMALE

5b. White bib absent or <= 4 cm and back of head primarily barred . . . . .
. . . . . . 6

6a. Crissum with > 6bars . . . . . . . . . . . . . . . . . . . . . . . .
FIRST-YEAR FEMALE

6b. Crissum white or with few (<= 6) bars or spots . . . . . . . . FEMALE,
AGE UNDETERMINED

Of the birds of known age in this study, one male of l3 (8%) could not be
accurately
aged with this key. All females of known age used in this study could be
aged correctly
by means of this key, but in some cases females for which age could not be
determined
using this key might be encountered.

The Snowy Owls with bursae of 5-11 mm would be classified as adults using
the key
presented above.

-- 
Don Crockett
Great Blue Media Works - http://greatblue.com
West Hartford, CT



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