We have all seen the harrowing images of people and their pets trying to escape the effects of Hurricane Harvey. What we don’t see as much are the desperate efforts of wildlife doing the same. There is one exception. A Coopers Hawk who has now been given the name Harvey became an internet sensation after it took refuge from the storm in the front seat of a cab. The driver discovered the bird after getting back in and found the frightened creature unwilling to leave. It is now at a wildlife rescue center and will most likely return to the wild soon. But what of all the others?
It would seem that of all the wild creatures, birds would have the greatest chance of survival because they have wings to carry them away from the dangerous storms. But they do not have a radar system to warn them of what is coming or lies ahead. They may sense changes in barometric pressure and this can affect behavior, but many times they are caught nevertheless in the crosswinds and rain and storm surges.
The time of year can play a big part too. As it happens, Hurricane Harvey arrived early in the migration season, so there are many of the smaller songbirds (that you have been giving your best bird seed to all summer) and a lot of shorebirds that have begun the southward journey. They are more likely to perish under such difficult circumstances. Some of these birds, exhausted by the effort of fighting the winds may find themselves pushed back to places they left a day or two before. Others may struggle onward and travel with the eye until the hurricane dissipates. There is one account of a radio-tagged Whimbrel (a larger shorebird) that flew through Hurricane Irene and made it out safely on the other side. It’s unlikely that little warblers and thrushes could do that.
These are the direct effects of being caught in a hurricane, but there are lots of indirect effects as well, when the waters subside and winds die down. Then one can see the destruction of nesting and roosting sites; the loss of food supplies or foraging sources; the increased vulnerability to predation.
Short-term response before the original vegetation and invertebrate life recover can include shifts in diet, foraging sites or habitats, and changes in reproduction. Destruction of vegetation is the most serious effect for upland terrestrial bird populations – those feeding on nectar, fruit and seeds. Some small populations of birds may risk extinction, especially if they exist in small isolated habitats. How quickly a remnant population recovers will depend on their ability to find nesting sites and recruit others of their kind from undisturbed patches of habitat.
An example exists in an area in New England where a series of hurricanes knocked down most of the trees in 1938. Afterward, the density of breeding birds went up for those birds that favor second-growth and openings, such as Mourning Warblers. There are always winners and losers when habitat changes, but sometimes the losers are those who can least afford it.
It might seem callous, but whenever a hurricane or tropical storm comes inland, you will find birders in the region who will race to lakes and rivers to see if any oceanic birds have been deposited there.
One of the big questions in the coming months is what will happen to the Whooping Cranes that normally return to the Aransas Wildlife Refuge each fall. In 1941, there were only surviving 15 whooping cranes and they all lived in Texas. There are about 350 whooping cranes currently in the western population and 63 additional birds hatched and fledged this summer in Canada, which is a record.
In the coming weeks scientists and others will see how the hurricane reshaped the string of barrier islands and how it might affect cranes and other wildlife, especially those that do not migrate.
According to Tim Gruenwald, North America programs director of the International Crane Foundation, based in Baraboo, “It’s going to be a long time before we know what the impacts will be on both the environment and the food resources,” Researchers will measure the salinity of the brackish water and judge the effects of potential pollution on crabs and other sources of food. They’ll also watch how cranes respond. One of the fears all along has been that some catastrophe could befall this small endangered population in Texas. That is one reason the Crane Foundation has spent more than $10 million establishing an eastern population in Wisconsin.
By Kate Crowley