I have been reminded by
several people that a brown eagle MIGHT be a female
or it MIGHT be a juvenile of either sex. I knew
that, but had leaned towards calling the eagle
a female because it was so very large. But...
that doesn't mean I'm right, so I should have
been more equivocal in my description.
The erudite scholar, Jan Hersey (master proofreader
for the 2nd Ed. of the SE AK Douglass cruising
guide), sent me a good explanation and a quote from
the David Sibley bird book. I'm going to
pass her comments on so we can all learn more
From Jan Hersey:
"Now about this eagle--how do you know it's
a female? I believe the coloration is simply that
of a juvenile. Takes about 4-5 years for them
to acquire full white tail and head and eye changes
from brown to yellow, as does beak. Females are
larger than males, otherwise there's no difference.
I've taken a fascinating class from Bud Anderson
at Padilla Bay on raptors. Think he gives it in
Seattle too, for about 5 weeks, during Feb., when
Skagit Flats are loaded with some 16 varieties.
I'll send you a web link to his organization if
Here's what my David Sibley book says on eagles:
"Adult distinctive, with white head and tail.
Juvenile dark with white underwing coverts, whitish
streaks on tail, and pale belly. Takes 4-5 years
to acquire adult plumage; after one year develops
white patches on belly and back, and after two
years white on head and yellow bill begin to develop."
I'd guess this one might be starting its 2nd year
as the book shows a first year with an all-brown
belly." Another amazing factoid is that they're
almost full size as soon as they fledge (leave
the nest). We have a juvenile that's been hanging
out around our house, though there aren't nearly
as many eagles around as earlier in the spring."
Many thanks to you, Jan, for sending this on.
I continue to appreciate your terrific skills
and vast knowledge base.
M/V Royal Sounder