July 1, 2002
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 https://ccbirding.com/
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Whooping crane production surveys were carried out in Wood Buffalo National
Park near Ft. Smith, Northwest Territories, Canada June 18-23, 2002 with
30+ hours of aerial observations by Pilot/Biologist Jim Bredy and Canada
and U.S. Whooping Crane Coordinators Brian Johns and Tom Stehn. In
general, I rated production as slightly below average, though not too bad.
1. A 49th and 50th nest were located in addition to the 48 nests found by
Brian Johns in May. Cranes were still sitting on two eggs in both of these
late nests. All 50 nesting pairs were located in June and checked for
2. Our June surveys in 2002 accounted for 33 chicks, including 5 sets of
twins. This compared with 39 chicks and10 sets of twins in 2001. From
this, I anticipate between 10 and 20 chicks will make it to Aransas this
3. Six cranes were sitting on eggs at the end of the survey on June 23th.
Thus, the final number of chicks hatched is not yet known. In 2001, the
final total of chicks equaled 44.
4. During the survey, we documented the loss of one of the twin chicks,
leaving 32 chicks with 4 set of twins. This compares with end of survey
results of 38 chicks with 9 sets of twins in 2001, 28 chicks with one set
of twins in 2000, 35 chicks with one set of twins in 1999, 32 chicks and no
twins in mid-June 1998, and 43 chicks and 4 sets of twin in 1997.
5. Surveys were done approximately two weeks later than 2001 because of
the late spring thaw. The nesting ponds were still frozen the first week
in May. All the chicks seen during the surveys conducted June 18-23 were
small and appeared to be similar in age. Even with the later survey dates,
7 cranes were observed incubating eggs during the survey.
6. Eight color-banded birds were accounted for on the June flights.
7. The Mustang Lake cranes seen by most visitors to Aransas do not have a
chick. The female from this pair was killed hitting a power line in Texas
in the spring migration, 2002. The male was seen with a new mate on the
traditional nesting territory in both May and June, but did not nest.
8. An estimated 7 known pairs failed to nest in 2002, one less than last
summer. Thus, there are 57 breeding pairs in the AWBP. This is four less
than last summer, and way below the potential 68 wintering pairs noted at
Aransas in the 2001-02 winter.
9. The winter territories of 24 of the 57 breeding pairs are not known. A
vocalization study initiated by Dr. Bernard Wessling that shows promise of
identifying individual pairs is ongoing.
10. Two of the 50 nests were located outside the Park boundary in the
Lobstick and Nyarling River drainages, the same two pairs as last summer.
11. Approximately 125 whoopers were sighted in June, accounting for 82% of
the total population of 173.
12. Water levels in the crane ponds were above average in June. Given
what looked like excellent water conditions, it is presumed that the late
spring thaw may have a negative impact on production.
13. The decrease in the population last winter and this summer's
disappointing production may possibly extend the predicted 10-year drop in
the whooping crane population that occurs at the start of every decade,
with a low for the decade predicted for 2001. This 10-year cycle in
whooping cranes is totally unexplained and does not appear to fit with
precipitation data from Ft. Smith, N.W.T. or water levels in Wood Buffalo
National Park. If the pattern continues, the population should start
increasing in 2003.
16. The USFWS Partanavia twin engine aircraft used in the mid-June
surveys provides unmatched visibility. The knowledge of CWS
biologist Brian Johns in locating nests and pairs is superb. The
surveys foster Canada-U.S. cooperation and provide a week for the
whooping crane coordinators from the two countries to exchange ideas
and help plan future research activities and overall recovery
objectives. In 2002, they worked on final changes combining the
Canada and U.S. whooping crane recovery plans into a single document.
I thank USFWS Endangered Species - Region II and the Canadian
Wildlife Service for funding this worthwhile trip.
TOTALS: 50 nests found,
33 chicks, 5 sets of twins,
32 chicks alive on June 23, including 4 sets of twins
6 cranes still sitting on nests
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