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 22 March, 2006 of the Aransas National Wildlife Refuge and
surrounding areas found 143 adults and 20 chicks =163 total.
Recap of cranes observed on the flight: (163)
adults + young
Refuge 45 + 5
Lamar 6 + 0
San Jose 26 + 4
Matagorda 50 + 8
Welder Flats 16 + 3
Total 143 + 20 = 163
Remarks: Finding cranes was difficult throughout the flight because of dark
overcast skies. As many as 25 cranes could easily have been
overlooked. Crane movements to freshwater dugouts and prescribed burns also made
it more difficult to find all the cranes. Nevertheless, the
census total was so low that it is estimated that 20-30 whooping cranes may have
started the migration, or up to 14% of the flock of 215.
It is still early for the bulk of the whooping cranes to head north. I do have
some evidence that the migration has started. One whooping crane was present
March 11th 16th on the Platte River in Nebraska. We believe this was the
whooping crane that wintered with sandhills in extreme south Texas until around
March 3 and thus migrated more on the earlier schedule of the sandhill cranes.
No sandhill cranes were seen at Aransas on today's flight, with sandhill numbers
already having peaked on the Platte River. A birdwatcher reported seeing 3
whooping cranes northwest of Fort Worth, Texas on March 19th. This is right on
the expected migration path of the cranes, and his observations sounded
credible. Two whooping cranes were confirmed present on the Platte River on
March 24th. With the low number of cranes found on the census flight and
knowledge that whooping cranes can leave in late March, it seems likely that
some are currently flying north.
Conditions are tough for the whooping cranes at Aransas right now, with few blue
crabs to eat and high water salinity forcing them to fly inland to get
freshwater to drink. Two days ago, I walked to numerous ponds looking for crane
tracks and their droppings. From the material I picked up, I found mostly shells
about the size of the fingernail on my smallest finger. Think how many of these
tiny shelled critters the whooping cranes would have to eat to get enough
calories, and then all the grinding up of these shells their stomachs would have
to do to digest all that material to get the small bits of meat.
Habitat use on today's flight included 4 cranes in open bays, 6 standing on
shell roads, 7 others on uplands (including 2 on a disked firebreak and 2 using
hog rootings), 21 on prescribed burns, and 24 near sources of fresh water.
Fifteen of the cranes were on a refuge prescribed burn conducted March 21st. The
drought in Texas is continuing with rainfall deficits resulting in high
salinities that force the cranes to seek out fresh water to drink. The drought
is rated as 'severe' on the coast and as 'extreme' in the Texas Hill Country
including San Antonio. Bay salinities at the refuge are 25 parts per thousand.
Tides have risen dramatically since February, measured at 2.8 mean low tide on
today's flight. The rise in tides is correlated with fewer cranes being found
in open bay habitat. On today's flight, only 4 cranes were in open bays,
compared to 47 on Feb. 15th when tides were much lower.
On today's flight, the cranes at several locations seemed more 'bunched up', a
tendency sometimes observed in early spring before the migration. Six cranes
were on the Big Tree Marsh, 11 were on Ayres Island/South Rattlesnake, and 5
cranes were on Long Reef. Several of the cranes looked 'dingy', indicating an
ongoing molt of body feathers.
Interesting locations on today's flight included the following:
a) Widowed female W-nil was with two other cranes on a prescribed burn.
b) The Victoria Barge Canal family group was at a windmill pond just east of the
Corps of Engineers dredge material site at Swan Point.
c) The Dewberry Island pair was on the uplands of the D H Texas Investments
property proposed for development near Port O'Connor.
d) Seismic operations were ongoing next to the North Lamar crane territory with
that pair found on the adjacent Big Tree marsh.
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/