Poor-will is a bird that is related to the Whip-poor-will.
It is found in the western states of the United States in
deserts and areas with little water.
When it chirps, it sounds like “poor-will”.
from: Rare & Elusive Birds of North
America by Bill Burt
These birds are about 7-8 inches in size.
They are mostly brown but have tiny, square, white patches at the
corners of their tails.
Poor-wills lay two eggs on the ground twice a year.
Adult birds who are caring for the eggs or newly hatched chicks can
begin a “sleep state” called torpor
but they seem to fight doing it. This
could be because torpor will slow down the growth of the chicks and lessen
their chances to live.
Sources disagree if the
Poor-will can be called a true hibernator.
Some say they are not because they even go into this “sleep like”
torpor when they are waiting for prey.
Hopi Indians were known to call these birds “the sleeping one”
because of this. Other sources
show that the birds do enter a daily torpor.
The body temperature of the bird drops more than 35 degrees lower
than normal. This fits in with
In 1949, a
man named Edmund C. Jaeger is said to have been in a California desert
when he found a Poor-will in between some rocks.
The bird was motionless when Jaeger picked him up [although he did
open one eye]. Jaeger came
back a year later and found the bird motionless again.
Jaeger found that the bird’s temperature was 65.9 degrees on an
85 degree day when its normal temperature is 105.
No amount of handling or yelling at the bird would wake him up.
This fits in with hibernation,
In 1962, Earl
Lathrop was hiking with a man named Professor Milliken.
It was reported that they found a bird “sleeping” in the bare
sand under a small bush. The
men picked the bird up and found it to be cold and it didn’t fly away or
move at all.
research, we think these birds go into ‘sleep-like’ torpors for short
periods of time [24-48 hours]. If
the weather is extreme—hot or cold—they do it.
If their food source of flying insects isn’t around, they will go
into torpor. Food [even if it
is INSECTS] is fuel to the body. When
the Poor-will goes into its temporary torpor—or sleep state—its heart
slows and temperature drops. This
means that the bird won’t need as much food to live.
The food already in its body will last longer because it isn’t
using much energy in sleep. This
is a way that creatures adapt to
where they live, weather conditions, and droughts
Back to Hibernation