July/Aug 2011 - Chippewa Nature Center

It’s time to say good-bye to orioles. WHAT? They just got
here! It’s true, orioles arrived just a couple of months ago
in early May, but what can I say? They have a job to do, they
do it, and then they move on!
Male Baltimore orioles usually arrive in late April, while
females show up about a week later. Courtship, mating
and nest building begin immediately; eggs are usually “in
production” within two weeks of the arrival of the females.
The famous oriole nest begins with the female wrapping
long strands of plant fiber, especially milkweed, Indian hemp,
dogbane and grasses, around flimsy branches near the top
of a tree. When she has a sizeable tangle of material hanging
from the branches, she begins weaving them in a seemingly
haphazard fashion, pulling strands through from this side or
that until a rounded pouch is created. Lastly, she lines the
inside of the pouch with hair or fine plant material.
During the eight-day construction project, the male is of
little direct help to the female, though he does sing and
fight other males, freeing her from distracting neighbors.
The male will stretch for a look inside the nest or to feed
the young, and knows the nest well enough to remove
cowbird eggs, but doesn’t enter the nest itself.
Baby orioles usually fledge from the nest by late June, which
leads to why I suggested you go ahead and say good-bye –
female orioles leave the territory almost immediately after
the young fledge! They spend a solitary couple of weeks
Photograph by Audrey Diadiun
Nature Notes – Orioles
4 Chippewa Nature Center www.chippewanaturecenter.org
Photograph by Audrey Diadiun
molting new feathers for the long fall migration, then begin
wandering south. The male is left to tend to the scattered
young and defend the territory. That doesn’t necessarily
mean you won’t see female orioles around, it’s just that by
July, you probably aren’t seeing the same females that nested
in your yard.
Male orioles are much more reluctant to leave the territory
than the female. Even after the young can fend for themselves
and have left the family ranch, males stay put, molting for the
upcoming migration even while they defend what seems to
us to be a pointless territory. By mid-September, even they
are heading south.
“South” is a long way off for orioles. Migrating at least as
far as Mexico, many fly on to Central America or even the
northern parts of South America. They will spend only a
few months there before heading back for their whirlwind
breeding season ‘up north.’
Janea Little
Senior Naturalist