Dear
Journey North,
We
did a census flight over the refuge on April 19th. All
but 7 of the 237 whooping cranes (3%) have started the migration
from Aransas. I estimate that 65 birds started migration
since the last flight on April 10th. Sighting reports in the
migration corridor
tell us that the Whooping Cranes are currently spread out across
North America, and some have reached southern Canada.
All
Juveniles Migrating
All the juveniles have departed Aransas. This includes
the “twin” juveniles
that had stayed behind when their parents left on migration. The
cranes still at Aransas are all believed to be subadults, or
non-breeders.
Since they won’t pair up and nest in 2007, these birds do
not feel the same urgency to pack their bags and leave the food-rich
marshes of Aransas and face the long, hazardous trip north.
Healed
Crane: No Urge to Migrate?
Three of the birds at Aransas may be the 3 cranes that failed
to migrate north in 2006. Yes, they spent all summer at
Aransas! One of the three suffered a severe
injury as a juvenile in April, 2004. I think it was either bitten
by a poisonous snake or was hit in the head with the talons of
a raptor. The bird
nearly died, with extreme swelling of the neck and head observed. The bird
did not eat for up to 10 days. It spent lots of time sitting down in the marsh — something
cranes rarely ever do. The crane got better and seems fine now, but somehow
it seems that the urge to migrate was knocked out of it. I think the bird
is a male. I wonder what will happen when it gets a mate — and
the mate is in the habit of migrating. Who will the win the discussion about
should we stay or should we head north for the summer?
"Senior Citizen" Bird Death on Migration
The total flock size was revised down on April 18 by one bird, (from 237 to
236 birds) when a dead Whooping Crane was found in a farm field in North Dakota.
The cause
of death was unknown, but it appears the bird had a broken neck. The bird will
be shipped to wildlife health experts
to see if they can figure out what happened. The bird had a red band on one
leg. When photos of the band were sent to me, I identified the bird as r-Y,
a male crane hatched in 1983, making it a very old bird.
(How old?)
Besides its age, the bird was special
for other reasons:
- It
first nested in 1986 and brought its first chick to Aransas in
1987. In 21 years of nesting, it successfully brought seven chicks
to Aransas. It was still a very productive male, having brought
six chicks to Aransas out of the last 10 years.
- The
dead bird and its mate both were equipped with radio collars
in the early 1980s, recalled Stehn. “We called them the ‘radio
pair.’ Not only did they produce seven offspring, but they
provided us with a lot of valuable information about whooping
crane movements.
- It
was involved in the fastest whooper migration across the United
States ever recorded,” he related. In the fall of 1983,
this bird and its parents were in a flock of six whooping cranes
that landed near Pierre, S.D. on Nov. 8. They were found on the
Texas coast just three days later.
Photo North Dakota Fish and Game Department
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