often ask: What is the highest number of cranes anyone
has ever counted at Aransas? I did my
first count in fall 1982. Only 73 whooping cranes
were present that winter. The good news is that the flock has
grown. This week I flew over the refuge to
count cranes for
season and my
best estimate for the peak population this winter
is 232 adults + 38 young= 270. "Best estimates" are
a part of science, but I don't
have as much faith in its accuracy as I
do in most years. Here's why:
has been my most frustrating winter at Aransas. This week's flight
indicates that so
far 11 Whooping cranes have died this winter at Aransas.
the wintering population (11 out of 270). We have just one or
in normal winters.
11 out of
146 Whooping cranes died at Aransas. In the last 20 years, the current winter
as the third worst in terms of mortality (deaths). Why
is this happening?
|Drought is causing problems in crane habitat.
|| Wolfberries are scarce.
||Blue crabs are scarce.
and fresh water for the cranes is scarce because of the prolonged drought,
or period of dryness, in Texas. Crab numbers dropped through
when hungry cranes were arriving after their 2,700-mile migration
from Canada. The crabs had moved out into the deeper bays. Normally
cranes will eat the fall wolfberry crop when crabs are few.
But the drought made wolfberries scarce too. Not only are their
normal marsh foods scarce, but the drought
has made the marsh water saltier than cranes can drink. They
to fly farther in search of fresh drinking water. Conditions
this extreme have not been recorded at Aransas NWR in the last
years. The habitat is not nourishing them after their long migration
from Canada. And summer nesting may be affected; research done
by Dr. Felipe Chavez-Ramirez in 1994 documented that up to 37%
to nest following a poor blue crab winter at Aransas NWR.
take heart. You
can look forward to hearing about some of the wonderful
crane individuals and pairs I have
at Aransas. You'll agree that their stories give us a lot
Aransas National Wildlife Refuge