Whooping Crane Census Flight
February 24-25, 2009
The eighth aerial census of the 2008-09 crane season at
Aransas was conducted February 24-25, 2009 with USFWS
observer Tom Stehn in a Cessna 210 piloted by Gary
Ritchey of Air Transit Solutions of Castroville, Texas.
Viewing conditions were very good for the survey,
although strong winds made for a very choppy ride.
We found 238 whooping cranes, but time limitations
required us to fly at greater speeds making it likely a
few whooping cranes were overlooked. Strong tail winds
and full power gave us at one point a maximum recorded
speed of 198 mph on our GPS.
Whooping Crane Numbers
The estimated peak winter flock size remains at 232
adults + 38 juveniles = 270 total. However, the last two
census flights have documented additional mortality that
has occurred at Aransas. I estimate the current flock
size to be 228 adults + 25 juveniles = 253, but this
figure may change depending on future observations.
Mortality this winter is currently estimated at 4
adults/subadults and 13 juveniles totaling 17 whooping
cranes. This is a loss so far of 6.3% of the wintering
population (17 out of 270). The all-time worst winter on
record was 1990 when 11 out of 146 (7.5%) whooping
cranes died at Aransas. In the last 20 years, the
current winter ranks as the second worst in terms of
mortality, but we still have one month to go. The 3rd
worst winter in 1993 showed a 4.9% loss at Aransas (7
out of 143). Mortality in the 2008-09 winter (17 birds)
must be added to the 34 whooping cranes that left
Aransas in the spring of 2008 and failed to return in
the fall. Thus, 51 whooping cranes have died in the last
12 months, or 19.2% of the flock of 266 present at
Aransas in the spring, 2008.
Three dead whooping cranes have been picked up this
winter; two were emaciated. The wing from a juvenile
whooping crane was picked up by refuge staff in the
North Pt. Pasture on February 13th. The remainder of the
carcass was in the mouth of an alligator at a freshwater
dugout. This chick from the North Dunham Point family
had separated from its parents as observed by staff on
January 29th and February 11th. It presumably was sick
and/or emaciated, a factor that contributed to its
separation and made the juvenile vulnerable to
One juvenile whooping crane was confirmed on the Platte
River in Nebraska on February 20th. This is presumably
the juvenile that had over-wintered in Oklahoma and
probably moved north with sandhill cranes.
Sightings near Aransas
Three whooping crane subadults continue to use farm
fields south of Austwell. They were seen in a pond next
to an agricultural field.
Management practices are aiding the cranes this winter.
Cranes on the flight included 28 observed at man-made
fresh water sources, 9 on burned uplands, 13 on unburned
uplands mostly foraging for tubers where feral hogs have
rooted up the earth, 18 at game feeders, 1 on a shell
road, and 20 in open bay habitat. Some water is starting
to move back into the coastal salt marshes, although
much of San Jose Island remained as dry tidal flats.
Salinities remain high, measured at 30 ppt in the refuge
boat canal. The drought rated as exceptional shows no
sign of ending in central and south Texas. Many counties
have imposed prescribed burn bans due to the fire
Blue crabs are still scarce due to the drought. The
refuge is continuing its program of supplemental feeding
using corn. A moderate response by the whooping cranes
has been observed with 100 photographs taken by remote
motion-activated cameras in the past week of whooping
cranes at refuge feeders. Other animals eating the corn
include feral hogs, deer, raccoons,
grackles and sandhill cranes.
The USFWS used up to 2 airboats the week of February
23rd to pick up abandoned crab traps in the crane area.
This was done in conjunction with a program organized by
Texas Parks and Wildlife Department to pick up traps all
along the Texas coast. Volunteers running private boats
picked up many traps on February 21st.
By Tom Stehn - Aransas National Wildlife Refuge
Tom Stehn, Whooping Crane Coordinator
U.S. Fish and Wildlife Service
P.O. Box 100
Austwell, TX 77950
(361) 286-3559 Ext. 221
fax (361) 286-3722
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Where applicable, CWS stands for Canadian Wildlife
Service; USFWS is US Fish and Wildlife Service. Crane
monitoring involves cooperative efforts and support by
both countries, plus many volunteers and non-profit
organizations along the way.