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The View from Sapsucker Woods An old black-and-white postcard surfaced the other day, showing several people watching birds through the Lab’s observatory window. Remarkable in this picture is a huge, leafy oak tree at the pond’s edge. It’s the very same red oak we now look at as a magnificent dead snag. Ospreys, herons, kingfishers, and flycatchers routinely perch on it, adding to its attraction for Lab visitors. The idea that a dead tree can be magnificent seems foreign to many people, yet these natural sculptures indeed display some of the most intrinsically beautiful shapes in nature. Moreover, the beauty in a dead tree is magnified a thousandfold once we appreciate its vital roles in the natural system. In my yard a few days ago, I marveled at a Hairy Woodpecker giving evening display calls near the top of a tall, dead ash. Between calls the bird tapped vigorously and extracted a few last meals for the day from under the flaking bark. I studied Hairy Woodpeckers for several years in Florida, where they are rare and rapidly declining. Yet here in Ithaca, they are common and increasing. Dead trees explain this seeming anomaly. In Florida the Hairy Woodpecker is confined to pine forests, once widespread across the peninsula. Through the millennia, these great southern forests routinely burned (as evidenced early this summer). Although these pines have evolved enormous tolerance for fire, many--especially the younger ones--do die when a big fire sweeps through. As a consequence, Florida’s Hairy Woodpeckers show extraordinary dependence on burned pine stands, where dead snags support a rich, if fleeting, supply of beetle larvae. Today, however, a century of fire suppression and even-aged timber management has left most of Florida without the key resource required to sustain Hairy Woodpeckers. It is worth noting that the only three stomachs preserved from Ivory-billed Woodpeckers contained exactly the same species of beetle larvae as those eaten today by the dwindling hairies. I have long suspected that the ivory-bill--which was a pine-forest woodpecker requiring many times more resources than its smaller relatives--was wiped out by exactly the same force that is destroying Florida’s hairies today: the absence of recently dead trees. Any birder who searches for woodpeckers in Europe encounters the same principle, which has been at work on that continent for 1,000 years. Many European forests are "squeaky clean," having been used for firewood gathering or manicured as parks for centuries. In most of western Europe, birds that depend on dead trees are scarce indeed. In contrast, the forests of northeastern North America are on a century-long rebound, as are the ubiquitous beavers that help supply so much fodder for the woodpeckers. The hairies in my yard benefit from both events. The most vibrant landscapes contain dead and dying trees. Landscapes cleaned of their senile limbs and rotting trunks harbor just a fraction of the species they once hosted. If you are lucky enough to have hairies in your yard, treasure the dead snags in your neighborhood. They breath life and diversity into the woods. -- John W. Fitzpatrick Louis Agassiz Fuertes Director |
