Bad Timing, Global Warming, and the Pied Flycatcher

Global warming will affect the natural world in unpredictable and dangerous ways. The Pied Flycatcher gives us an example of what we can expect from climate change.

Until now, the most interesting thing about the European pied flycatcher was its mating habits. Well, the way they catch insects in flight (thus the name, flycatcher) is pretty interesting too, but mating is more interesting than eating in my book.

Many male flycatchers will seek out a second mate after they've bred once. Very rarely they seek out a third mate after that one.

Despite the demands of expanded territory, they are rarely deadbeat dads. Usually they will help out with the feeding of the first brood as well as the second. This has created some confusion for the animals. Two different male flycatchers have been observed feeding nestlings in the same nest - usually a grave breach of territory that the primary male would not allow.

The flycatcher spends most of its time in northern Europe and Britain. They carefully watch the length of the days. When shadows lengthen and the nights get longer, they know it is time to fly south. Around October of every year, they start a migration that will take them to western Africa. Here they spend the winter soaking up sun, again watching the days for the sign to return home. While the birds fly back north, spring is bringing new life to the northern latitudes.

Insects, with a much shorter lifecycle than the birds, react to the warming temperatures rather than the length of days. As the pied flycatcher arrives in Europe from its winter vacation, builds its nest and lays eggs, the caterpillars are coming out. They are easy pickings as they munch on leaves. By the time the flycatcher eggs hatch, the caterpillar population is at its peak, and the flycatchers hatchlings have plenty of food.

Usually. The comfortable rythm of the seasons has been changing lately. Birds like the flycatcher who watch the length of days are keeping the same schedule they always have. Insects, tuned in to the warmth of spring, have begun to start their lives earlier.

As the winters come earlier, flycatcher populations have plummeted.

We ought to keep in mind that this is not just about the flycatcher. The caterpillars are also affected by this. The flycatchers are an important regulator of moth population. Who cares about moths? Well, caterpillars feed primarily on leaves, and some caterpillars, like those of the Gypsy moth, can wreak havoc on a forest by defoliating trees. This effect can easily cascade, as the trees provide habitat and sustenance for a host of other creatures.

The pied flycatcher is a relatively common bird, and it is not considered to be a species of concern by most conservation groups. But it can teach us a lot about the effects of global warming.

Photo by Sergey Yeliseev. Some rights reserved. Used by Permission.