Most of our woodpeckers in Oregon, and particularly Portland, are resident, meaning they stay put year-round, and this fact of life shapes much of their breeding strategy. Rather than doing what our flashy warblers do—migrate, and find a new mate every year upon returning—many woodpeckers are likely to keep their same mate for as long as they two shall live, and will often maintain the same territory, together, throughout. In fact, the sense of place is so strong for Pileated Woodpeckers, which can have huge territories of hundreds of acres, that the surviving bird will stay in their territory even after losing their mate (many other birds would abandon the territory in the hopes of finding a new mate).
Staying in the same territory, at least among woodpeckers, also leads to females having much more of a role in territorial defense. Both sexes will perform drumming, which is the woodpecker equivalent of a songbird’s song, where the stylized rhythm serves as a territorial display, and perhaps also functions to strengthen the pair bond. It’s thought that the equality between the sexes of Red-breasted Sapsucker in territorial defense may contribute to that species being identical between male and female, a rarity among woodpeckers.
Female woodpeckers not only help hold down the fort, they can be quite picky about where they roost. Hairy Woodpecker males and females will each maintain their own roosting (sleeping) cavities year-round. When time comes for nesting, the male will generally excavate a new cavity (or two), and the female will inspect it. If it’s up to her standards, they will mate, and she will then lay eggs in the nest. But rather than “moving in,” as most female birds do, she will continue to go back to her own cavity at night, leaving the male to tend to incubation and brooding after the lights go out. Both birds will take turns with parental duties during the daylight hours, straight through until the young become self-sufficient.
Not all woodpeckers are emblems of equality between the sexes. Its well-known that male and female Downy Woodpeckers partition their foraging locations based on sex, with males feeding towards the smaller outer branches at the tops of trees and in low bushes, and females sticking to the larger branches towards the middle of the tree. Less well-known is that when the males are removed, the females happily move into the males’ territory. It seems the males dominate those locations because they have the best food supply.
But the winners of the most unique family life certainly goes to the Acorn Woodpecker. These “clowns of oak woodlands” are well-known for their dependence on acorns to survive the winter, leading to their construction of huge “granaries,” trees stuffed tightly with acorns, sometimes numbering into the tens of thousands. This unique feeding style has led to some truly bizarre social structures.
Acorn woodpeckers are highly social, and are a rare practitioner of “polygynandry,” meaning that both males and females will take multiple mates. It can be hard to even keep track, because the females will all lay their eggs together in the same nest cavity – at times with internecine warfare, with a female destroying an egg if she finds one laid before hers. Males will engage in their own bouts of jealousy, often following around a female that they have mated with, preventing other males from mating with her until she lays an egg.
Once the eggs have hatched, however, all of the males and females in the group then work together to care for the young, and are joined by a number of non-breeders, generally first-year birds from the previous year’s brood, who will also help feed the baby birds.
As we enter mid-summer, our woodpeckers are busy raising the next generation, particularly in the mountains where the breeding season is slightly later. So it’s a great time to go out and appreciate some of these unique behaviors yourself.
For more information on woodpeckers, the Peterson Reference Guide to Woodpeckers of North America, by Oregon woodpecker expert Steve Shunk, is available from the Portland Audubon Nature Store.
Brodie Cass Talbott is an educator with Portland Audubon, teaching classes on all manner of birds, including woodpeckers and owls. He also leads birding tours and writes the Portland Audubon Rare Bird Alert.