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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 was conducted November 27, 2007 of the Aransas National Wildlife Refuge and surrounding areas.  The total number of whooping cranes located was 257.  I estimate that about 97% of the flock has completed the migration with 4-8 whooping cranes still in the Flyway.  Four whooping cranes have been confirmed in the past few days in the Flyway, so the addition of these cranes brings the estimated size of the flock to 261.

 

Recap of cranes found at Aransas (257) and in the Flyway (4)

 

 

adults + young

Refuge

  63 + 10

Lamar

  12 +   1  *

San Jose

  56 +   8

Matagorda

  71 + 11

Welder Flats

  18 +   7

Flyway

    3  +  1

Total

223 + 38 = 261

 

* The 13 whooping cranes found on Lamar was a record number for that area.

 

The whooping crane survey was conducted in a Cessna 210 piloted by Gary Ritchey of Air Logistic Solutions of San Antonio, Texas.  Observers were Tom Stehn and Darrin Welchert.  Viewing conditions were excellent, but flying transects facing into the sun in the late afternoon made it difficult to find all the cranes on the north end of Matagorda Island and Welder Flats.

 

Results provided a record-breaking count of 220 adults + 37 chicks = 257 total.  Additional whoopers in the flyway are one bird in Saskatchewan sighted Nov. 24, two cranes sighted at Cheyenne Bottoms WMA, Kansas on Nov. 26, and one juvenile crane sighted with sandhill cranes at Muleshoe NWR in West Texas on Nov. 27.  Additional birds may turn out to be one crane seen in the farm fields just southwest of Aransas on Nov. 24, and one crane seen in the rice country north of Welder Flats on Nov. 17.  However, until these last two single birds are sighted again, it cannot be known if they have moved to the traditional salt marsh wintering area at Aransas and were counted on todayís census flight.

 

An estimated 16 whooping cranes have arrived since the last flight completed on November 17th.  A very strong cold front that hit the Texas coast the evening of November 21st brought excellent migration conditions to Aransas for 4 days and allowed the additional cranes to get to Aransas. 

 

The estimated flock size of 261 is a result of the excellent production of 40 juveniles sighted on the nesting grounds in August.  With 37 juveniles at Aransas and 1 in West Texas, survival of the juveniles since August has been excellent.  Adult survival has also been good.  Mortality of white-plumaged cranes between spring and fall, 2007 is at most 13 birds.  This is calculated by taking the spring flock size (236), adding the number of juveniles that made it to Texas (38), and subtracting the current estimated flock size (261).  In the past two years, mortality between spring and fall has been above average and totaled over 20 birds each year. 

 

On todayís census flight, there could have been crane movements that resulted in a duplicate count involving a few birds.  One additional family group was found on Matagorda Island but in hindsight was conservatively considered as a duplicate sighting.  Future flights should be able to determine if there actually is a 38th juvenile at Aransas.

 

On the flight, no cranes were found on prescribed burns or at fresh water sources.  A prescribed burn was done along the refugeís East Shore Road during the flight.  Three cranes were found on upland prairie on The Reserve at St. Charles, a piece of property on the Lamar Peninsula slated for development of a canal lot subdivision.  Three cranes were on a dike near a wild game feeder on the Johnson Ranch on the Lamar Peninsula. 

 

A family group of 1 adult + 1 chick was found this week south of Pringle Lake on Matagorda Island.  Previously, this grouping had been sighted on the refuge and at Welder Flats.  Iím speculating that the single adult is a female that lost her mate after nesting and unable so far to defend a territory and thus is moving around considerably.  A 2-adult family group was present in front of the refugeís observation tower where the 1+1 grouping had been last week.

 

Since this was the third census flight of the fall and most of the cranes are at Aransas, Iím getting a handle on the location of crane territories as crane pairs return to defend traditional areas.  Tour Boat Captain Tommy Moore has noted a new duo carving out a territory just north of the refugeís Dunham Bay.

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/