Netta Smith and I made a very long trip just to see a bunch
of chickens strutting around. But these were special "chickens," and
it was worth the trip. We drove from Seattle all the way to Dubois, Idaho,
where we had reserved a blind in mid April at the edge of a Greater Sage-Grouse
lek. This species, Centrocercus
urophasianus, is the largest North American grouse. The males are not
turkey size, but at over three kilograms in weight, they are big chickens!
Males begin to assemble at display grounds, which are called
leks, in early spring, often while snow is still on the ground. Then they may
display for as long as three months. The leks can contain just a few males or
rarely up to several hundred. Males arrive at dusk and may remain through the
night, but highest activity is usually around sunrise. When fully into it, males
perform their complicated display 6-10 times/minute. Males keep the tail erect
and fanned at all times, but then at intervals they step forward and inflate their large
esophageal pouches.
The pouches swell and protrude through the snow-white neck
feathers and the whole neck and breast move up and down together with the wings
rotating forward and back. The expanded sacs make loud plops, and these sounds
dominate the auditory experience at a lek, although the loud songs of
meadowlarks often add to it. The males also make a swishing noise with their
wings and a rattle with their tail feathers, an impressive collection of
nonvocal sounds.
The smaller, duller females are not much in evidence,
but they move quietly through the lek, apparently looking for a male that
impresses them. If they find him (it may take several visits), they crouch down and copulation takes place.
Some males are outrageously successful, very few individuals accounting for
most of the matings that take place on the lek. We don't know exactly what
gives them that advantage, but it may be that some males never get to mate!
At the Dubois lek, there were over 50 males at sunrise. A
fly-by Prairie Falcon scared about half of them away with a sudden burst of
flights in all direction. Another bunch left a bit later, and the few females
present left at that point, but a dozen males stayed behind and displayed for
another hour after the sunlight hit them. The closest were 30 feet from the
blind and were wonderfully oblivious to the telephoto lenses poking out at them
and the constant click of shutters.
After the female copulates once, she has sufficient sperm to
fertilize her clutch of about eight eggs. She wanders back into the sagebrush
and builds a nest, often under a shrub, incubating the eggs and then
shepherding the young around as they grow. Males take no part whatsoever in
parental care, quite typical of grouse.
The last few birds flew away from our lek about two hours
after we arrived, leaving us with a feeling of awe at how natural selection had
molded such showy, yet precise and stereotyped, behavior the sole purpose of
which was to gain a mating opportunity.
The town of Dubois puts on a bird festival every spring,
Dubois Grouse Days. Check their website for next year's show. Reserve a blind
for yourself. You don't have to be a photographer to appreciate the spectacle,
but I would advise bringing a camera!
Dennis Paulson
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