We have all heard first-hand about the devastation caused by hurricane Harvey. The news was full of video clips of destroyed buildings and of communities trying to put their lives back together.
Now that process is underway, people are beginning to ask the less pressing questions like how wildlife survived. An estimated 60,000 people visit the Aransas National Wildlife Refuge each year mostly in the fall and winter when the Whooping cranes are in residence.
Luckily, those birds are still in Wood Buffalo National Park in northern Canada where they are preparing their chicks for the 2500 mile migration to the Coastal Bend Region of Texas that will start in about a month. Now that the flood waters have subsided in most places, people are concerned about what the cranes will find when they reach their traditional winter habitat.
Aransas NWR has been closed to the public since the hurricane and crews have been clearing toppled trees and making the roads passable again. They are just now reaching the salt marshes and coastal prairies where the Whooping cranes spend the winter.
On the surface things look good but three important factors must be evaluated before we know what obstacles these endangered birds may face this winter.
The water in and around Aransas is a brackish mix of salt water from the Gulf and fresh water from the Guadalupe River. That delicate balance sustains the blue crab population, which along with the pistol shrimp and clams makes up the primary diet of wintering Whooping cranes. The last time the water salinity in the bay was disturbed, then by severe drought, a large percentage of the wintering cranes didn’t survive.
U.S. Fish and Wildlife Service staff have yet to determine if the series of fresh water ponds that the Whooping cranes use for drinking are contaminated. Most of that habitat is extremely resilient. Its vegetation evolved to withstand regular floods, but modern floods bring with them another hazard that wasn’t part of their evolution. Plastics, tires, human debris and even barrels of oil have been found in critical crane habitat. The solids can be cleaned up eventually but the liquid contaminates take much longer, and are far more expensive to remove.
So if the Bay water is still brackish and there is fresh water to drink that isn’t contaminated with pollutants, the only naturally occurring flock of Whooping cranes may still have a good winter home. That’s important because they are bringing with them a record number of chicks this year. At the last count in Canada, 62 chicks have fledged including four sets of twins.
Storms of increasing intensity and rising sea levels threaten the critical habitat used by Whooping cranes both in Texas and Louisiana where a reintroduced flock of non-migratory Whooping cranes now numbers more than 50.
When the Eastern Migratory Population began, it was intended that the birds would winter in the salt marshes on the Gulf Coast of Florida. Obviously, our birds had other ideas because they are now spread out over much of the eastern flyway. Some birds winter at St Marks NWR south of Tallahassee while others prefer Wheeler NWR in Alabama. Some only travel as far south as Goose Pond State Wildlife Area in Indiana.
That distribution was once considered a shortcoming of this project but maybe it will safeguard the birds from any one weather event. Maybe it makes them more adaptable than the natural flock that seem focused on a small area of precious habitat with an uncertain future.
Storm events are only one of the hazards that threaten the critical habitat in Texas. There is the possibility of chemical spills, erosion, human encroachment, invasive species like black mangrove or even an avian disease. That’s why the Whooping Crane Recovery Team began the Eastern Migratory Population and other flocks in the first place and why they are more important now than ever.
We have an unprecedented one hundred birds in the eastern flyway; the first since the last nest was reported in Wisconsin in 1878. It is a priceless asset but it is not yet self-sustaining. We need unrelenting enthusiasm and continued support to ensure that Whooping cranes are disseminated enough to survive any single threat.