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April 9, 2003
The following report is forwarded with permission from Tom Stehn, USFWS biologist and US Whooping Crane Coordinator.
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: firstname.lastname@example.org. Other information, including archived copies of these reports, can be found at the Texas Whooping Crane web site at http://www.ccbirding.com/
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An aerial census of the Aransas National Wildlife Refuge and surrounding areas on April 09, 2003 estimated the number of whooping cranes present at 113 adults + 8 young = 121 total. The flight indicated that 5 whooping cranes had started the migration since the previous flight on April 2.
RECAP OF CRANES OBSERVED:
adults + young total
Refuge 20 + 2 = 22
Lamar 4 + 0 = 4
San Jose 23 + 0 = 23
Matagorda 52 + 6 = 58
Welder Flats 14 + 0 = 14
Total 113 + 8 =121
Results and Conclusions: Clear skies throughout the day provided excellent census conditions. All areas were covered in 6.8 hours of flight time.
Today's flight found more cranes (121) than the previous flight on April 2, thus making an adjustment necessary to the number of cranes estimated present last week (revised upwards to 126). The higher number of cranes located resulted from the excellent visibility under clear skies during today's flight, whereas last week skies had been a high overcast. Thus, 63 cranes (34.2% of the flock) so far have started the migration. Cranes have been sighted recently in North Dakota and Nebraska, so the flock is currently spread out between the Texas Coast and the Canadian border.
The migration appears to be on schedule, with 14 cranes (7.6% of the flock) departing by March 26, an additional 44 cranes (23.9%) having departed the following week by April 2nd, and 5 cranes (2.7%) having departed between April 2 & April 9. These 5 cranes were one family group and one pair. Conditions for migration were very good on April 3-4, the most likely time that the 5 cranes started north. Conditions were less favorable on April 5-6, and totally unfavorable April 7-9 as a cold front brought strong north winds to the Texas Coast. The total of 63 whooping cranes that have migrated include 7 family groups and 21 adult pairs. All 35 subadults estimated present in the flock were located on todays flight. A majority of the cranes remaining on the Texas coast are expected to start migration April 12-13 when the winds are forecast to turn around.
Specifics / Interesting Locations: The five cranes that started migration since last week were the Pat's Bay family on San Jose, and the Grass island pair at Welder Flats. The crane pair visible from the refuge observation tower is still present. The chick that had separated from its parents on Matagorda continued to be closely associated with one other crane. A subadult with a drooping wing was located as a duo on Matagorda's Shell Reef Bayou. Last week, this bird was a single about 2 miles further south. Ten cranes were unusually close together by Long Reef on San Jose, although still split into groups of two. This is sometimes observed just prior to migration.
Habitat: On today's flight, no whooping cranes were in uplands, on prescribed burns, or at fresh water sources. Two cranes were in open bay habitat in Shoalwater Bay.
- Tom Stehn
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Patty Waits Beasley
Corpus Christi, TX