Tom Stehn, Whooping Crane Coordinator,U.S. Fish and Wildlife Service has prepared a lengthy, detailed report concerning the 2008 – 2009 whooping crane population. The following summary of the report provides much new information. To read the entire report, you may download it by clicking here. The download is a PDF file.
The Aransas-Wood Buffalo population (AWBP) of whooping cranes reached a record population of 270 at Aransas in December, 2008. The number would have been substantially higher but for the loss of 34 birds that left Aransas in the spring, 2008 and failed to return in the fall. Faced with food shortages from an “exceptional” drought that hammered Texas, record high mortality during the 2008-09 winter of 23 cranes (8.5% of the flock) left the AWBP at 247 in the spring, 2009. Total flock mortality for the 12 months following April, 2008 equaled 57 birds (21.4% of the flock). The refuge provided supplemental feed during the 2008-09 winter to provide some cranes with additional calories. Two whooping cranes failed to migrate north, but survived the hot and dry 2009 Aransas summer.
A below-average 2009 production year in Canada with 22 fledged chicks from 62 nests was half the production of the previous summer and is expected to result in a break-even year for the AWBP. Threats to the flock including land and water development in Texas, the spread of black mangrove on the wintering grounds, and wind farm construction in the migration corridor all remained unabated in 2009.
The Cooperative Whooping Crane Tracking Project documented 79 confirmed sightings of whooping cranes in the U.S. Central Flyway during fall, 2008 and 38 sightings in spring, 2009.
The captive flocks had a very good production season in 2009. Twenty-nine chicks were reintroduced into the eastern migratory population, bringing that flock to 106 total birds. Three chicks of high genetic value were held back for the captive flocks.
Production in the wild from reintroduced flocks in 2009 was disappointing. In Florida because of the continuing drought, only 4 of 11 pairs nested and fledged 1 chick. In Wisconsin, all 12 nesting pairs abandoned their nests. Five or 6 pairs re-nested hatching 2 chicks, but neither chick survived. The major hurdle of nest abandonment in Wisconsin must be overcome for that reintroduction to have a chance of success. Although efforts to clear this hurdle should continue, the Recovery Team recommended starting reintroductions in different areas, both looking for other release sites in Wisconsin for the migratory whooping cranes, and starting a nonmigratory flock in Louisiana.
In 2009, total production could not quite keep up with mortality, with the total population of wild and captive birds dropping from 538 to 534 during a12-month period. The drop was primarily due to the high mortality experienced by the AWBP.