Wade Harrell, U.S. Whooping Crane Recovery Coordinator
Whooping crane migration is well underway. We estimate that less than 20% of the population is still on the Texas coast wintering area and that number should quickly dwindle over the next week or so. A significant portion of the population appears to have made it across the border into Canada. Right now we have whooping cranes spread out from the wintering grounds nearly to the breeding grounds in Wood Buffalo National Park. Though the cranes seem to leave in mass, they actually have staggered departures and leave in small groups. This is important as it ensures survival of the species. If they were to all leave together and encountered bad weather or some other catastrophic event, it could put the whole population in jeopardy.
This will be the final Whooping Crane Update for the season. We expect to begin posting Updates once again next season and are considering other ways to quickly disseminate wintering whooping crane information.
The final 2013-14 Annual Whooping Crane Survey will also be made available on this site within the next few months.
Whooping Cranes on the Refuge
Cranes that could be seen from Heron Flats and the observation tower on the refuge appear to have departed. But there are many other interesting wildlife species to see so don’t hesitate to come out and enjoy other spring wildlife watching opportunities on the Aransas National Wildlife Refuge (NWR)!
Texas Whooper Watch
We have had a few reports of whooping cranes spotted in migration, including observations from Tarrant and Johnson counties in North Texas. While we didn’t have nearly as many whooping cranes use inland sites this winter, Texas Whooper Watch still provided vital information during both fall and spring migration. Please continue to keep watch for whooping cranes and send in your reports.
As of Sunday, April 21, four of the marked birds that we are actively receiving data on were still on the coast. Of those in migration, 12 were in Saskatchewan, eight in the Dakotas, four in Nebraska, two in Oklahoma and one in Texas. Based on this information and other observations, it is likely that more than 80% of the birds in the Aransas/Wood Buffalo population are currently migrating north.
Documented Mortalities During Winter 2013-2014
This season we documented four whooping crane mortalities on and around Aransas NWR. The first mortality was an injured subadult that we captured and transported to the San Antonio Zoo for treatment.. Unfortunately that bird died 30 days into treatment. We collected an unmarked adult bird at a waterhole on the refuge, and the necropsy identified bobcat predation as the likely cause of death. Two additional marked birds died in February but, because carcasses were not located (only radios), necropsies could not be conducted. Thus cause of death is unknown but predation is suspected.
Texas City ‘Y’ Oil Spill
For those who have been following the news, you know that we had a significant impact from the Texas City Y oil spill on the Matagorda Island Unit of Aransas NWR and home to a large portion of the wintering whooping crane population — and a number of other threatened and endangered species. Fortunately for the whooping cranes the oil did not make it through any of the Gulf passes or into the coastal marsh habitat used by whooping cranes. The oil that did hit was on the Gulf-side beach of Matagorda Island below the dunes. While there was no direct impact to whooping cranes as they don’t regularly visit this portion of the island, the Service was concerned that disturbance associated with the clean-up efforts may impact whooping cranes and other wildlife species. We worked closely with the Coast Guard, Texas General Land Office, and the responsible party to avoid and minimize clean-up disturbance impacts to the refuge’s natural resources to the greatest extent possible. Part of that work involves having numerous Service biologists and other staff members monitor cleanup crews and making sure best management practices are followed. We hope that clean-up activities are completed in the very near future and the Island’s wild inhabitants can continue their normal lives! Learn more about the spill here.