I'm pleased with the response I got to my comment that Chestnut-
backed Chickadees seemed to be dominant to Black-capped Chickadees at
my feeders. As this isn't a controversial subject, I'm assuming the
responders won't mind if I quote them, in the order received. It
certainly looks as if what I observed is widespread, yet it's not
included in the Birds of North America accounts for either species.

"I've not noticed that pattern on my feeder, but I have noticed
differences between the two species. The CB tend to be more
'cautious' at the feeder, more prone to grab a seed and fly to a bush
to eat it, rather than eating from the feeder like the BC will. And
the 2 species are seldom at my feeder at the same time. It seems that
the BC will fly in at different times than the CB are around (or vice
versa). When they are around at the same time (not often) it seems
that the CB are more likely to move away than the BC, but that could
be just because they are more cautious at the feeder. I'll watch for
an dominance behaviour from now on, though." Guy McWethy

"Yes, I have the same thing in my yard. The chestnut-backed
chickadees will cut the line on the black-capped ones, and pretty
much act like the suet feeder and the tree it hangs from belong to
them." Liz Copeland

"As per your posting on Tweeters...at my cabin I definitely see the
Chestnut-backed Chickadees dominate the Black-capped and I also see
the Chestnuts wait for certain others to come to the feeders and
walnuts first. It is as though they have a "take a number" system and
wait for their turn in their line of dominance. Sometimes if one
"misreads" its turn and get to the feeder another will come in a
chase it away while it takes a seed." Idie Ulsh

"I also have noticed this, and for the second year in a row, the
Black-capped try to occupy the chickadee house, but are ousted by the
Chestnut-backed." Dawn Bailey

"I have noticed the same thing. Chestnut-backs are much bolder than
Black-caps. They are always the first to investigate some new food
source, and will let me get much closer to the feeders before flying
off. A small group of chickadees has been eating pine nuts out of my
hand, and the group this past winter mostly consisted of 5 Chestnut-
backs and one Black-capped. And the BC always waited until all the CB
had flown off before coming forward. Now, however, only one CB is
still coming." Christy Anderson

"I too have noticed that Black-capped Chickadees wait their turn at
my feeders, even the one with several openings. And, yes, I've seen
the Chestnut-backed Chickadees "elbow" their way in on the oh so
polite Black-caps." Barbara Johnson

"Yes,I've noticed the same thing: the Chestnut-backed seem to always
take dominance over our Black-capped on the feeders outside our
kitchen windows. However, I guess I always put it down to the fact
that we have more of the former--and an occasional belligerent junco
will chase either of them off! " Murray Hansen

"When I was an undergrad in New Hampshire, I did a project for my
animal behavior class looking at aggression and dominance in mixed-
species flocks. The species I saw were black-capped chickadee,
tufted titmouse, and white- and red-breasted nuthatches. My project
was limited in duration and scope, but it seemed that the chickadees
and titmice tended to approach the feeder first, but that the
nuthatches would then usurp them. I described it as a parasitic
social relationship where the chickadees and titmice located food
resources and then the nuthatches took over and feasted. After much
more training in the study of animal behavior, I would certainly
hesitate to make such claims based on the small amount of data I
collected (a week or so of feeder visits at a single feeder by an
unknown number of flocks)." Ryan O'Donnell

"I don't have any direct experience with these two species together
so I tried to look up any past published articles regarding
interactions between the two. The only thing I could find was a
study looking at interactions between Black-capped and Mountain
Chickadees. They found that Black-cappeds generally dominated
encounters at feeders with Mountains but that it really varied and
depended on sex, experience in the area, and other factors. I also
found a study that looked at sympatric habitat use by Chestnut-backed
and Black-capped and they found no aggressive interactions between
the two species. The author concluded that these two species are
well separated in foraging areas within the same habitat (CBCH
foraging high in canopy and in conifers compared to BCCH foraging
lower and in deciduous trees) and this limits the interaction between
them and reduces competition. Interesting that you witness CBCH
being dominant as I would have predicted BCCH being dominant due to
size as well." Jeff Kozma
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Dennis Paulson
1724 NE 98 St.
Seattle, WA 98115
206-528-1382
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