Birds & Hurricanes

Birds have been dealing with hurricanes for millions of years and have developed a remarkable ability to survive. Whether it is a type of ESP (extra sensory perception) or not, birds process acute sensory perceptions and sensitivities to changes in air pressure, vibrations and low frequency sound waves that alert them to weather changes such as a coming hurricane. Sensing a storm, birds either hunker down and ride it out, or flee. In some instances, they move in the wrong direction getting trapped inside a hurricane’s eyewall. Here they are forced to move with the storm until it losses strength or they become exhausted and land to ride out the remainder of the storm.

A couple weeks prior to Hurricane Matthew I watched in amazement a Ruby-throated Hummingbird alternately sitting on a small tree branch and flying back and forth to its feeder in 20 to 25 MPH wind. Hummingbirds, as with other song and woodland birds have specially adapted toes that automatically tighten around their perch. This enables them to hold on to branches when they sleep and in high wind. Birds also have the ability to fluff their feathers adding additional protection from the rain and cold. Woodpeckers and other cavity nesting birds may ride out storms in their cavities. However, in the high winds and driving rain of a hurricane such adaptations and behavior may help but can’t explain how they survive. Two days after Hurricane Matthew visited Seabrook Island. the same or perhaps another Rudy-throated Hummingbird was waiting on the same branch watching me put the feeder back up. Had he hunkered down somewhere close-by or flown out of harm’s way?

Ruby-throated Hummingbird - C Moore
Ruby-throated Hummingbird – C Moore

One of the most written about instances concerning a birds encounter with a hurricane is the story of Machi, a Whimbrel. Fitted with a satellite tracking tag in 2009, Machi had been followed for two years while making seven 2,000 mile trips between her breeding grounds near Hudson Bay to her wintering grounds in the Caribbean Sea. She had traveled a total of over 27,000 miles. Prior to being shot by a Guadeloupe hunter in 2011, Machi on her last trip was tracked traveling hundreds of miles out of her normal migration route as she skirted Tropical Storm Irene.

A tagged gannet approaching the southern shore of New Jersey as Hurricane Sandy made landfall there, made a sharp U-turn and headed back north toward Long Island and out to sea along the continental shelf where it waited out the storm. However not all birds go around a storm. In 2011 another tagged whimbrel, nicknamed Hope, was tracked flying through Tropical Storm Gert off the coast of Nova Scotia, entering at 7 MPH and emerging at nearly 90 MPH.

Shore and ocean-faring birds have been detected in recent years by polarization radar that were trapped in the center of a hurricane. Trying to fly away from the higher winds of such storms these birds enter the back edge and work their way to the calmer center. Here they become trapped, being forced to fly long distance without food or rest. Becoming exhausted, these birds are often forced to take refuge from the storm landing, particularly as the storm passes over a large lake or other water body, and ride-out the rest of the storm.

As Hurricane Hermine made landfall along Florida's Gulf coast, radar detected an interesting phenomenon: birds trapped flying inside the calm eye of Hermine. The red shaded area on the image to the right shows the birds swirling inside Hermine's eye just before landfall.
As Hurricane Hermine made landfall along Florida’s Gulf coast, radar detected an interesting phenomenon: birds trapped flying inside the calm eye of Hermine. The red shaded area on the image to the right shows the birds swirling inside Hermine’s eye just before landfall.

Called “hurricane birds”, these birds may be transported great distances. Coastal shore birds may be transported hundreds of miles inland and Caribbean Island species may flee to coastal areas of the United States. Birders frequently take advantage of this phenomena and search for new bird sighting following a hurricane. Many first area records occur at such times however unfortunately many of these translocated birds do not survive.

The most important impact of a hurricane on birds may be its impact on the environment. Flooding by a saltwater surge and/or freshwater flooding from accompanying rain may have dramatic short and long term impacts on vegetation. Beach erosion may destroy critical feeding and nesting areas of shore birds. Forest vegetation may be flattened and stripped of leaves making it uninhabitable to many birds. Fruits and berries, nuts, acorns, and other food sources may be lost. Many cavity dwelling birds such as woodpeckers and owls may lose nesting trees as they frequently snap off at the cavities.

In 1989, Hurricane Hugo resulted in the loss of nearly 60% of the remaining population of the endanger Red-cockaded woodpecker as a result of an estimated 90% of the trees with nesting cavities within the Francis Marion National Forest being flattened. The same storm resulted in the loss of 40% of all the known American eagle nests in South Carolina.

Hurricanes do kill birds and change the ecosystem, however, one animal’s loss is another’s gain and healthy populations do survive. Tree top dwelling birds may lose much of their habitat but those requiring lower, shrubby level vegetation such as the whip-poor-will will flourish. Fallen trees, branches and stripped leaves result in increased light and photosynthesis on the forest floor. As the fallen vegetation rots it fertilizes and simulates new growth creating important food sources. Fallen vegetation also creates millions of new nooks and crannies that will become home for many bird species and numerous other forest creatures.

Submitted by:  Charles Moore

 

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Author: sibirders

SEABROOK ISLAND BIRDERS / “watching, learning, protecting” Seabrook Island Birders (SIB) are residents, renters and guests of Seabrook Island, SC who have an interest in learning, protecting and providing for the well-being of the incredible variety of birds that inhabit Seabrook Island throughout the year.

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