Greetings all!
The following report is forwarded with permission from Tom Stehn, USFWS
biologist and US Whooping Crane Coordinator.
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An aerial census on 21 December, 2005 of the Aransas National Wildlife Refuge
and surrounding areas estimated the number of whooping cranes present at Aransas
as 187 adults + 29 young = 216 total. One additional whooping crane is in
extreme South Texas in Hidalgo County near Hargill brings the current estimated
flock size to 217. This is believed to be the 2004 juvenile that had separated
from its parents last fall and had spent the 2004-05 winter with sandhills near
Bay City, Texas north of Aransas. One adult and one juvenile have died this fall
at Aransas, accounting for a peak population of 189 + 30 = 219. In additional,
two reports from good birders were received on December 21 of whooping crane
pairs in flight near El Campo and west of Blessing, Texas, both locations north
of Aransas by about 30 miles. If these reports can be confirmed, and presuming
they were of different pairs based on the distance between reported sightings,
the peak flock size for the winter may reach 193 + 30 = 223. Last winter's peak
population was a record 217. On December 14, three whooping cranes in flight
were reported by birders between Green and Mission lakes on the Guadalupe Delta
Wildlife Management Area located about 15 miles north of Aransas. Thus, although
I think the flock has completed the migration, there may be a handful of
whooping cranes currently with sandhills north of Aransas in south Texas.
Recap of cranes observed on the flight: (216)
adults + young
Refuge 60 + 10
Lamar 4 + 0*
San Jose 40 + 4
Matagorda 67 + 11**
Welder Flats 16 + 4
Total 187 + 29 = 216
* The movement of the Long Reef family from San Jose to Lamar put 7 cranes on
Lamar.
** Sets the all-time record for whooping cranes on Matagorda Island by one
crane.
Remarks: Good to excellent viewing conditions were present throughout the day
with scattered clouds present for only part of the morning. All of the crane
winter area except for Burgentine Lake was flown in an 8.0-hour census. An
additional area searched was marshlands north of Hynes Bay near Tivoli.
With very good viewing conditions, uncertainty about the numbers of cranes
present was caused primarily by crane movements. Uncertainties included 2 cranes
on San Jose in the Fenceline territory that moved during the transects and could
not be re-located, and 2 cranes on the refuge seen in flight soaring above the
census aircraft. In addition, although the number of cranes at Welder Flats
remained the same as last week, the distribution of cranes made it possible that
the Dewberry Island pair was overlooked. I included 4 of these 6 uncertainties
into the flock total and will try to confirm totals sighted on the next census
flight. On any given census flight, there are always movements that create
uncertainty, and only by doing multiple census flights can an accurate flock
total be derived. On today's flight, the banded family group seen on its Long
Reef territory on San Jose Island at 0810 hours had flown across Aransas Bay and
was found on the Lamar peninsula south of Holiday Beach at 1130 hours. Major
movements such as this can really hurt the accuracy of a census count, but in
this instance, reading the bands on the family allowed me to document the
movement and prevent duplication on the count.
The big surprise of today's flight was the apparent recent arrival of a new
single unbanded adult with a juvenile. This 1+1 grouping was sighted on
Bludworth Island across from the Lobstick territory. Nearby were 2 subadult
cranes. Two additional subadults flew in, forming a group of 4. The 4 walked
towards the 1+1, with the lead bird in the 4 in definite threat postures. Later
on in the flight, the grouping of 1+1 had moved and was located close to the
north end of Dunham Bay. Reports from a tour boat on December 22 placed this 1+1
group in Sundown Bay just north of the Pump Canal. The other group of 1+1
containing a banded adult female has remained on her territory at N. Pipeline
Flats. The 1+1 group added to the 214 cranes estimated present at Aransas last
week gives a total of 216 at Aransas, the number seen on today's flight.
Interesting locations on today's flight included a single visible from the
refuge's observation tower at Mustang Lake, an indication that the resident
territorial pair has either not arrived or is wintering elsewhere in the crane
area. The family group that in the fall roamed around the north end of San Jose
Island was for the second straight week located on the refuge, this week in
South Sundown Bay. The Middle Sundown Bay pair was apparently located in the
empty territory to their north situated north of the Pump Canal.
Interesting observations of habitat use on today's flight included 8 cranes on a
prescribed burn conducted at the refuge's Dunham Bay on December 15th, 13 cranes
at freshwater sources, and 6 cranes on gravel roads. Six cranes were in open bay
habitat, all at Welder Flats. Fourteen additional cranes were on different kinds
of upland habitat, including 2 at a game feeder on Lamar, 3 in feral hog
rootings on Matagorda Island, 3 in upland prairie, 3 in oak brush habitat at
Welder Flats, and 3 on dry sandflats. The amount of upland use including use of
a prescribed burn was a notable difference from last week's flight. This change
in type of habitat being used by the cranes is an indication that the main food
sources (crabs and wolfberries) are diminished and the cranes are having to
scramble to find other food items. This type of change in habitat use is
normally seen in most winters in late December through mid-February. The
relatively high salinities may also be promoting cranes to use upland areas as
some cranes fly to uplands to get fresh water to drink. Tides levels were
somewhat higher than last week, measured at 2.7 mlt on December 19. Limited
areas of mudflats on San Jose Island were exposed.
Tom Stehn
Whooping Crane Coordinator
U.S. Fish and Wildlife Service
Aransas NWR
P.O. Box 100
Austwell, TX 77950
(361) 286-3559 Ext. 221
fax (361) 286-3722
E:mail: tom_stehn@fws.gov
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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.
Anyone wanting to contact Tom about the report or the whooping crane projects
can reach him via email at: tom_stehn@fws.gov. Other information, including
archived copies of these reports, can be found at the Texas Whooping Crane web
site at http://www.ccbirding.com/
Patty Waits Beasley
Corpus Christi, TX
email: patty@ccbirding.com
web: http://www.ccbirding.com/