April 2, 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 02, 2003 estimated the number of whooping cranes present at
107 adults + 9 young = 116 total. The flight indicated that 54 whooping cranes had started the migration since the previous flight on March 26.
RECAP OF CRANES OBSERVED:
adults + young total Change from March 19
Refuge 22 + 2 = 24 - 20
Lamar 2 + 0 = 2 - 2
San Jose 21 + 1 = 22 - 14
Matagorda 46 + 6 = 52 - 13
Welder Flats 16 + 0 = 16 - 5
Total 156 +14 =170 - 54
Remarks and Conclusions: High overcast skies throughout the day provided good census conditions. All areas were covered in 5.8 hours of flight time.
Today's flight indicated the spring whooping crane migration had progressed with an additional 54 cranes having started the migration since the previous flight on March 26. Weather conditions during the past week were such that most of the cranes are estimated to have departed March 31 & April 2, although some cranes may have left March 27. Migration conditions were ideal on April 1 with southeast winds at 25 mph and sunny skies. On April 2, the winds were not as strong, and high overcast clouds were present.
The migration appears to be on schedule, with 14 cranes (7.6% of the flock) departing by March 26, and an additional 54 cranes (29.3%) having departed the following week. Thus, 68 whooping cranes (36.9% of the total of 184 cranes at Aransas) consisting of 19 adult pairs, 6 family groups, and 12 subadults have started the migration. The migration appears to be on schedule since the majority of cranes usually depart April 4-12. I expect most of the cranes to be headed north by the middle of April. This may be a year where it is advantageous to not leave early. It is still very cold up north. It was about 10 degrees F April 1st and still very frozen in Wood Buffalo National Park where the cranes will end up about one month
Specifics / Interesting Locations: 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 single on the south end of Matagorda, no longer with one other crane that perhaps had migrated.
Although cranes had departed from all the main wintering areas, crane departures were definitely not randomly distributed. For example, 3 neighboring pairs had departed from the south end of Matagorda Island, but the next 18 consecutive pairs on Matagorda were all present. Similarly on Welder Flats, 7 neighboring pairs were present, but the two pairs the furthest to the northeast had migrated. This fits previous observations that a pair of cranes starting the migration may influence their neighbors to also initiate migration at the same time or shortly thereafter.
Habitat: On today's flight, no whooping cranes were in open bay habitat, on prescribed burns, or at fresh water sources. Two cranes were on uplands on Matagorda Island.
- Tom Stehn
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Patty Waits Beasley
Corpus Christi, TX