The Wild Side: The secret life of whip-poor-wills
When I was young, our family would come up camping to a small lakeside campground in the American Legion State Forest near Sayner. Almost every facet of those camping trips seemed emblematic of the Northwoods: bald eagles flying overhead, the smell of campfires as we returned from evening fishing trips, clear water lapping at rocky shores—and in the middle of the night, the stirring call of the whip-poor-will. Whip-poor-wills are a fixture of Wisconsin bird life. Recognized by their distinctive call, perhaps second only to that of the loon, whip-poor-wills are readily heard, but rarely seen. Whip-poor-wills are a member of the nightjar, or goatsucker, family of birds. The name goatsucker came from a historic misbelief that these birds would drink the milk from goats at night. They have a very short but wide-opening bill, a large head and large eyes. These features make them look somewhat owl-like. They have very short, very small feet, pretty much useless for walking.
You have probably seen their close relatives, the common nighthawks, flying around the bright lights of a gas station or stadium in an urban area. You may have thought they were big bats at first, although they made a sort of buzzy “peent” sound. Nighthawks and whip-poor-wills are similar in a lot of ways, but nighthawks are crepuscular, meaning they are active at dawn and dusk. Whip-poor-wills are more nocturnal, meaning they are active after dark. Nighthawks do well around people, relying on rooftops for their nesting; whip-poor-wills stay in the woods where there are less people. Both birds eat large, flying insects like moths. They both migrate south for the winter, although nighthawks travel further south than whip-poor-wills. Both species sit lengthwise along tree branches, a behavior unique to the nightjar family.
Whip-poor-wills do not build a nest; they lay their eggs on the ground to hatch them. They synchronize the laying of their eggs with the moon phases, meaning their eggs will hatch 10 days before a full moon. This ensures that the parents will have the most available moonlight to allow them to hunt for insects to feed their chicks. Both parents work to raise the young, and the male protects the nest from potential intruders. They only lay two eggs, which has its pros and cons. With only two eggs, it takes less work to lay, hatch, feed and protect them. However, if the population drops, it takes much longer to increase numbers with such low recruitment.
According to the Wisconsin Breeding Bird Atlas, the bird’s numbers are lower than they were historically. Wisconsin DNR has listed the bird as a “Species of Greatest Conservation Need” due to its decline. Being associated with harvested or young forest, they probably boomed after the great cutover, and have begun getting squeezed out as forests have matured across the north. These birds are notoriously difficult to count. Because of their secretive nature and nocturnal habits, they are not readily evident during the time periods when other bird species are counted. What little information we do have on the nightjars tells us they have been in decline for the last 40 years.
Seven years ago, the Wisconsin nightjar survey was begun to help us get a handle on true population numbers. The survey method is deceptively simple: volunteers drive an established rural road route during the designated window of time and record the number of bird calls they hear. The results from previous years are impressive; not that we are counting a large number of birds, but that we are giving bird enthusiasts a chance to participate in management and help us develop and refine a survey of this type. This is one of several bird surveys with which you could become involved; there is also a secretive marsh bird survey, an owl survey, loon watch and a red-shouldered hawk survey. Go to dnr.wi.gov/volunteer/animals/birds.html to learn more.
Jeremy Holtz is a wildlife biologist with the Wisconsin DNR and writes a weekly column in the Star Journal. To contact him, call (715) 365-8999.