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March
30, 2007
Dear
Journey North,
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The
"Oiled" Family
More>>
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"Oiled" Family Found!
Last
time I told you that I have been watching a special family
group at Aransas this winter. I didn't find them on my last two
searches. Well, I found them on a recent flight to look for any
juvenile mortality that may
have occurred during winter. The good news is that I didn't find
any evidence of young crane deaths, but I DID find the oiled family!
The North Cottonwood family group had apparently been exposed
to oiled water during the fall migration and they got stained.
I identified
the family from a color band on the right leg of one of the
adults. Although I could not get a look at their bellies, no staining
was apparent on the feathers on the upper leg, indicating that
the birds have lost some of the staining present last fall.
I hope
to conduct flights every 7-10 days in April to document the upcoming
migration. Stay tuned
for the
counts!
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Great
Egret: Crane Look-alike!
Photo: Laura Erickson at Disney World
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It's
Hard to Identify a Whooping
Crane in the Sky
I want to write a little about the difficulty of identifying
Whooping Cranes. Sure, they are nearly five feet tall — taller
than any other bird in North America. But it is often hard
to get a good look at Whooping
Cranes
in migration to identify them correctly. That is because cranes usually
stay away from people during migration. Mistakes
People Make
Many people call me to report they have seen Whooping Cranes,
and often they are mistaken. Great Egrets are also all
white and tall, but have yellow bills
and no black on the wings. White pelicans in flight look extremely similar
to whooping cranes. Pelicans are also very large white birds with black on
the wings, and the long beak of a pelican can sometimes be mistaken at a
distance for the long neck of a crane. Remember, people
are often seeing these birds
flying high above them, maybe 1⁄2 mile away. The biggest difference
in flight is that the Whooping Crane legs stick straight out far behind their
body, whereas the pelican has very short legs that don’t stick out
at all.
Whooping Cranes are pure white except for black wing tips and black markings
on the face. Adult Whooping Cranes have red on the back of their head, but
it does not stand out the way the red crown covers the entire top of the
head of a Sandhill Crane. Juvenile Whooping Cranes in the spring have a few
rusty
brown feathers remaining on the body, and their heads and upper neck are
still rusty brown. The brown feathers are the feathers the birds had when
they were
very young chicks to allow them to hide from predators. As they grow larger,
the brown feathers are gradually replaced with white feathers.
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Is
this a whooping crane? >>
Photo Jeannette Parker, Florida
Fish and Wildlife Conservation Commission |
A
Confusing Kind of Crane
One other bird can make it very
difficult to identify a Whooping Crane. Sometimes the gray feathers
on a Sandhill Crane don’t develop
the right pigments and the feathers remain white. We call this a leucistic Sandhill
Crane, different from an albino although
they look similar. There have been 2 or 3 leucistic Sandhill Cranes on
the Platte
River (Nebraska) in March, making it more difficult
to identify several Whooping Cranes that have been seen
so far this spring on the Platte River, a big stopover
site.
A
LONE Juvenile: Was This Sighting Correct?
Reports came on March 20th on the Platte River in
Nebraska and on March 27th in South Dakota of a juvenile
Whooping Crane traveling with sandhills.
Both observers reported seeing some rusty brown feathers. These sightings
provoked lots of discussion. Was the Whooping Crane juvenile identified
correctly? I
think they were valid sightings. But … what was the
juvenile doing by itself since a Whooping Crane juvenile usually remains
with its parents during its first year? We
had a family group of
Whooping Cranes leave Aransas on March 8th. Had the juvenile separated
from its parents
somewhere during the migration and the youngster then sighted later
in Nebraska and North Dakota?
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Normal Behavior: Chick W1-06
Whooping
Crane juveniles normally complete the spring
migration with their parents. Then they go off on their own,
remaining in areas close
to — but not within — their parents' nesting territory.
This is what just happened with the first Eastern Flock Whooping
Crane chick hatched
in Wisconsin last summer. Chick W1-06 spent
its first
year with its parents (#211 and #217 in the new flock).
After migrating in the fall and wintering in Florida, this family
left
Florida
on
February
23,
2007 and
arrived back on
the parents'
nesting territory in Wisconsin on March 20, 2007. On March 23,
the juvenile was off
by itself, adjacent to its parents' nesting territory.
We
have never observed parent
cranes aggressively chasing off their juvenile, but somehow
they effectively communicate to their youngster that it is
time to go off on its own.
Soon the parents will be building a nest. The juvenile seems
ready to be independent
and will spend the summer by itself or with other Whooping
Cranes
that have not yet found mates. It’ll do just fine
because it learned from its parents all the skills needed
to survive.
Leaving
Parents Early
The separation of the juvenile whooping crane sometimes occurs
before or during the spring migration. I have documented
Whooping Crane
adults that
start the
migration from Aransas and their youngster stays behind. The juvenile
must be asking, “Where are you flying off to, Mom and Dad?” The
juvenile quickly adjusts and usually joins groups of other whooping
cranes to make the
migration. Sometimes the juvenile breaks off from the parents during
the migration. Once when I was radio-tracking a family group of
cranes and we had crossed
the border into Canada, the parents continued the migration a few
days later and the juvenile stayed behind. The juvenile was fine;
it later made it back to the summering area in
Wood Buffalo
National
Park on
its own. We had not observed any aggressive behavior by the parents
against their
juvenile. I think the juvenile had just decided that it was time
to go its own way.
Tom Stehn
Whooping Crane Coordinator
USFWS
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