Winter is the best time for finding wildlife tracks and sign, but before leaf-out in spring is second on my list. Being able to see longer distances without leaves blocking your view can reveal all sorts of activity. I recently showed you some examples of nests (https://www.pei-untamed.com/post/nests-of-birds-and-not-birds), and today we’ll look at Woodpecker sign.
PEI has seven species of Woodpeckers, several of them rare. While you may think of them as just noisemakers pecking away at trees (or worse, your house!) Woodpeckers play essential ecological roles. The holes they excavate provide starter homes for cavity-nesting birds that can’t create their own, such as Saw-whet Owls, Tree Swallows, Chickadees, and Nuthatches among others. They eat huge numbers of insects and so provide pest control services, especially for bark beetles and wood-boring insects. Fungi on Woodpeckers’ beaks helps speed wood decay which contributes to nutrient cycling the forest. And they provide food for dozens of other species of birds and mammals (more on this in a moment).
Not all Woodpecker sign is obvious. Northern Flickers not only drill holes, they also strip away the outer layers of dead trees in search of insects (Photo 1 by Jeff Matheson, used with permission). The result is something that could be mistaken for Porcupine sign if we lived somewhere that had them (no Porcupines on PEI!). While Flickers feast on wood-dwelling invertebrates, they also forage for ants and other insects on and just below the ground and also include seeds and berries in their diet.
The Pileated Woodpecker is our largest species and leaves unmistakable sign (Photo 2). These strong birds are about the size of a crow and can dig much deeper into trees than any of our other species. Pileated Woodpecker holes often have squared corners and they tend to follow the ‘rule of two’: at least two inches long, two inches deep, and with two-inch (or larger) wood chips below the excavation. These Woodpeckers would have been common across the Island historically but were believed to have been extirpated by 1900. The first modern-day sign was found in Eastern Kings County in 1987. Since then, Pileated Woodpeckers and their sign have been found in all three counties, though the species is still considered rare in the province.
If you’ve ever found horizontal rows of holes in a tree, you’ve found Yellow-bellied Sapsucker sign. Sapsuckers’ approach to feeding is the opposite of Pileated Woodpeckers’: rather than drilling deep into trees to get at juicy insects and larvae, they make rows of shallow holes to get the sap flowing so they can lap it up. That’s where providing food for other animals comes in.
Sap from Sapsucker holes keeps flowing even after the birds have left, providing leftovers for a range of insects, birds, and mammals. More than 40 different species have been recorded feeding at Sapsucker holes. I’ve seen Butterflies, Ants, Wasps, Blue Jays, Warblers, and Hummingbirds all do this, and last spring I caught a Red Squirrel in the act of getting a sweet treat thanks to a Sapsucker (Photo 3; you can also see the video of the Squirrel in action on my Facebook page).
Ecologists use the term “keystone species” to describe plants and animals so essential to their ecosystem that it would change dramatically if they were removed. Woodpeckers are among the keystone species here on PEI untamed!