By Jeannie Marcure
When I moved to a new neighborhood five years ago, I was fairly confident in my ability to identify the birds that frequent the Flathead Valley. However, that confidence was soon shaken when I met my new neighbors who were camping and building a house on the hill above us. Once I’d told them of my interest in birds, they asked me to identify the bird making that “rude sound” in the early morning and evening. Well, I didn’t have a clue! Of course I’m always up for a birding challenge and so after a few days of research and with the help of some friends, I was able to determine that the “rude sounds” were being made by a male Common Nighthawk making aerobatic displays over his territory . The loud buzzing or whooshing sound is created by the wind rushing through the primary feathers as he plummets rapidly toward the ground and then soars to dive again. This display is the nighthawk’s way of impressing females and is also used to scare intruders away.
In the years since, that sound and also the nighttime “peent” made by the nighthawks as they snatch insects from the air, have become some of my favorite summer sounds. The presence of the nighthawks may also explain why our neighborhood is relatively free of mosquitoes.
Nighthawks were often called “goatsuckers” because of the erroneous belief that they flew into barns at night and sucked the teats of goats dry. While this legend is not true, the mouth shape of the nighthawk makes it seem plausible. They have relatively small beaks, but a large gape is created when the shape of the lower jaw changes from a V into a semicircle as the mouth opens to take insects.
Migration data for the nighthawk shows them as Montana residents from June through September.. Not coincidentally, they arrive with the first hatch of insects and leave when the nights cool and the insect population dwindles. This year the nighthawks arrived in our neighborhood on June 2. Of course this late arrival may also be because they winter in Central and South America, making for a very long flight! Choosing a diet of flying insects including ants, moths, mosquitoes and small flies, these birds are real bug zappers, sometimes stuffing as many as 2000 bugs into their gullets as they fly open-mouthed through the night air. Interestingly, unlike most birds, nighthawks do not have a bony palate. Instead the upper jaw is lined with an unusual soft membrane which some researchers believe is sensitive to collisions with small insects and causes the mouth to snap shut upon impact.
Nighthawks nest on the ground in open arid, gravelly rural areas. Town residents often nest on gravel rooftops. Here again the soft membrane of the palate comes into use with the capillary rich tissue of the mouth and throat collecting heat which is then dispersed by gular (throat) fluttering and panting. This allows nesting nighthawks to survive very high temperatures. Incubation and brooding chores are shared by the parents. The two olive eggs with dark marks are hatched in 19-20 days and the precocial chicks leave the nest within a day or two and can fly in about three weeks.
If you’d like to see a Common Nighthawk this summer I’d suggest first familiarizing yourself with their sounds by listening to the recordings in the on-line Cornell guide.
Because their brown, black and gray coloring is camouflaged perfectly by their habitat, the presence of these small birds is most readily identified by voice. They will most readily be seen in flight at dusk and dawn where they can be identified by their long, thin rounded wings with conspicuous whitish bars near the tips. Listen for those “rude sounds” and scan the skies over open , rocky areas or give me a call and come enjoy an evening with the nighthawks from our deck!