A female downy woodpecker (Dryobates pubescens) scuttles along a tree, drumming fiercely to advertise her presence. The oscillogram depicts one of this individual’s drumming sequences. Both sexes perform drumming behaviors in the contexts of courtship and territory defense. They have exquisite modulation of their drumming signals, capable of producing and discriminating between drumming speeds that differ by just 9 milliseconds. Further studies have shown that drumming speed (or ‘cadence’) encodes information for species recognition, with woodpeckers responding more strongly to drums by their conspecifics than to drums by other co-occurring species. While drumming signals may convey information about species identity and social context, downy woodpeckers are not able to discriminate between individuals by drums and instead rely on vocal communication.
Downy woodpeckers are the smallest North American woodpecker species, adults reaching only about six to seven inches in length. Males are adorned with a bright small patch of red on the back of the head, while females lack the patch entirely, instead having their lateral white stripes join posteriorly with a black cross. The male pictured above was being pestered by territorial song sparrows (Melospiza melodia), and after a tumultuous landing, he jumped up to clench onto a thin perch in a daze. About a minute later he regained his strength and dashed away, all the while the sparrows continued to chirp incessantly.
Although woodpeckers are a common sight in the woodlands of central Missouri, most of the time they are knocking away and chirping high in the canopy. Three species remain to be photographed and added to this post: the red-headed woodpecker (Melanerpes erythrocephalus), hairy woodpecker (Dryobates villosus), and the yellow-bellied sapsucker (Sphyrapicus varius).
All woodpeckers in this post photographed in situ