Songbirds tend to be an agreeable bunch. They may squabble at the backyard feeder but, for most of the year, they live in harmony. In fact, during the colder months, mixed flocks of songbirds roam together, cooperating in their search for food.
However, when nesting season arrives, most male songbirds become territorial. Like bull elk, they charge at invading rivals, using their threatening calls and postures to keep others at bay; physical encounters are rarely necessary. This past weekend, a tufted titmouse noticed his reflection in our large picture window. Fluffing up his feathers, he developed an agitated shiver, produced a shrill, high-pitched warning call and flew toward the window, hovering just before the glass. Returning to his perch in the magnolia, he repeated this sequence numerous times before giving up and moving on.
Such displays are, of course, purely instinctual, driven by a primal urge to ensure that one's genes are passed on to future generations. Whether a titmouse or an elephant, the stronger, healthier and more persistent suitor wins the battle and, as a result, the future welfare of that species is enhanced. This is the basic principle of natural selection, the engine of evolution.
