Gale Force Migration
Bird migration is heavily linked to weather patterns and systems as they move across the country. In the fall, fast
moving northwest winds, especially ahead of a front, help speed migrating birds ahead of tempestuous weather. But fall migration coincides with another huge event in North America — hurricane season — and this seems to be an especially big challenge for migrating birds. As people prepare and hunker down for these major storms that sweep the Gulf of Mexico and the East Coast, some birds may have already been forewarned by their own natural instincts. Feeling the shifts in barometric pressure lets birds know that a storm is brewing. But it doesn’t mean they are out of harm’s way.
With this advanced warning, birds have a few options. They can try to outpace the storm by flying ahead of the outermost winds of the hurricane. Birds tend to move after a low-pressure system has passed, so if the storm passes to the east, favorable northwest winds will allow the birds to take off in time. Some birds, especially pelagic species may choose to enter the storm and find the calm eye or center of the storm. This may be a dangerous decision as birds could be forced to fly hundreds of miles without being able to land.
Some birds get the natural signal too late, and are caught in
winds that come up quickly. In these instances, they will look for any place to put down. If they are over water — to avoid drowning — tankers, oil rigs and anything floating serves as a safer haven than battling gale force winds which would surely be a losing battle. Seamen on the Gulf during hurricanes have tales of fallouts of sometimes hundreds of songbirds landing on their boats. And lighthouse keepers off the coast find they are often the only port in a storm, like this image above from the Machias Seal Island Lighthouse, Gulf of Maine.
But, many birds decide to stay put during these storms and often we wonder what exactly they do in those high winds and drenching downpours. They don’t have a lot of choices, so they hunker down, cling to perches and bide their time as best they with the rest of us. Although little energy is spent perching, birds still have to keep their bodies warm and their bellies full. There are undoubtedly high mortality rates amongst birds during hurricanes who get blown out to sea or are drenched and unable to keep their body warm enough to survive.
The after effects of the storm can cause serious problems for birds as well. Habitat changes are a major problem birds face after the storm has passed. Most birds will be heading south during hurricane season, but the habitat they may come back to in the spring could be changed forever. Sometimes habitat change is can be good for a particular species, but bad for another.
After weathering the storm, birds may find themselves displaced in obscure places. It may take them a few hours to get oriented, but they quickly try to make their way back to where they came from. In 2011 Hurricane Irene swept up the eastern seaboard and left white-tailed tropicbirds, which are typically only seen in the Caribbean, cruising the New York and New Jersey coastlines. Birders across the country are always interested to see what birds may be blown in after a hurricane. If you do find these vagrants, respect what the bird has had to go through to get where it is, and don’t cause the bird additional stress.
Birds small and large find ways to weather these storms. A radio-tagged whimbrel was tracked migrating right through Hurricane Irene as the bird made its way from Canada to Brazil on its annual migration. Birds are resilient creatures and continue to impress researchers with new discoveries on a frequent basis. Hurricanes hit hard and when they do we can only hope that most of the birds have left ahead of the storm.