Summary
Whip-poor-wills (Caprimulgus vociferus) showed significantly higher levels of locomotory, vocal, and nest activity during twilight and bright moonlight than under moonless conditions. Field observations and nest record card data indicated that Caprimulgus species usually synchronize their reproductive cycle with the lunar cycle. Hatching tends to occur during young waxing moons, presumably so that moonlight-enhanced foraging will be at a maximum while the dependent nestlings are an energy burden on the parents. Observations of foraging Whip-poor-wills suggest they are primarily visually oriented, unlike the bats (Chiroptera).
Methodology
I conducted fieldwork near Rideau Lake Narrows (44°43'N, 76°17'W), eastern Ontario, May-July 1983 and 1984. This was a region of marginal farmland, forest, rock outcrops, and many small lakes, where both Whip-poor-wills and Common Nighthawks (Chordeiles minor) were common.