People’s apprehensions intensified at night for very good reasons, including peaking adrenal hormones between 4:00 and 8:00 a.m., coupled with the loneliness of early morning hours. “Solitude, the night and fear makes all my danger double to appear,” wrote Henry Nevil Payne. Georg Christoph Lichtenberg reflected, “I have gone to bed at night quite untroubled about certain things and then started to worry fearfully about them at about four in the morning, so that I often lay tossing and turning for several hours, only to grow indifferent or optimistic again at nine or even earlier.”

— A. Roger Ekirch, At Day’s Close: Night in Times Past

In his wonderful project The Dictionary of Obscure Sorrows, John Koenig chooses the term “nighthawk” to vividly represent this experience:

n. a recurring thought that only seems to strike you late at night—an overdue task, a nagging guilt, a looming and shapeless future—that circles high overhead during the day, that pecks at the back of your mind while you try to sleep, that you can successfully ignore for weeks, only to feel its presence hovering outside the window, waiting for you to finish your coffee, passing the time by quietly building a nest.

The phenomenon of “mobbing” is well-known, where a group of smaller birds harass and chase a larger, predatory bird away from their territory. I see it all the time during the course of a typical day, with red-tailed hawks being plentiful in the area. As the name implies, though, their metaphorical cousins have evolved to prey at night, when the sparrows and wrens of optimism are sleeping and reluctant to be summoned to defense. I have yet to discover what sort of seed could tempt them to patrol in the small hours, but I will be glad to hang a feeder in my bedroom in the event that I do.