During your forest wanderings, you have probably stumbled upon a dead tree or two. No, not a log, not simply a rotten stump or remnant of a tree that once inhabited a space, but rather a refuge for a wide range of life: a Wildlife Tree. You may know these natural monoliths by a different name; such as snag, den tree or cavity tree. I prefer the name Wildlife Tree due to the image it evokes of a bustling entity just waiting to be observed. Far be it from a state of mourning; with their death, trees bring forth opportunity for new life.
Once a tree has died, many things are able to occur, including the magic of decomposition. Invertebrates, bacteria and fungi break down the tree for energy, and as they do, these nutrients are cycled back into the soil system, allowing for new growth. More often than not, a Wildlife Tree will have fungi springing up all over and within it with fruiting bodies—mushrooms—on display in autumn. The arrival of the decomposers is followed closely by primary cavity nesters looking for a snack and nesting site. These are the creatures that excavate a hole in the dead tree as a nesting site in preparation for raising the next generation. You guessed it; I’m referring to woodpeckers!
Here on Vancouver Island we are fortunate to have a multitude of woodpeckers, ranging from the toy-like Red Breasted sap sucker, to the regal Pileated woodpecker that inspired the most popular woodpecker of all—Woody, of course! Woodpeckers forage for food by clinging to the side of a tree with their specialized feet and drilling their beak so fast, that it is a shock they aren’t dizzy.
Depending on the species, they may then extend their extraordinarily long tongue into the larvae filled hole in the tree to collect their reward. The woodpeckers tongue also doubles as protection from brain damage during pecking, as it is so long that is actually wraps around the skull when not in use!
Woodpeckers may drill a distinct pattern of holes into the tree to draw out sticky sap which will act as a trap to collect insects for a crunchy buffet later on. In contrast to arboreal woodpeckers, the Northern flicker is often seen on the ground foraging for ants. However, like all woodpeckers, you can still count on the flicker to drum out a distinct beat on the nearest wooden surface to announce its territory or impress a potential mate.
Most local woodpeckers are distinct enough to decipher from each other except for our checkered friends; the Hairy woodpecker and the slightly smaller and shorter billed Downy woodpecker.
Industrious Downy woodpeckers are able to excavate an entirely new cavity for nesting in about 16 days, and they do this every time they nest. Often, woodpecker parents will line their nesting cavity with wood chips as well as use moss and lichen to conceal the entrance to create the safest home possible.
Typically the primary cavity nesters only use the hole they have created for one nesting season, which leaves an inviting, unoccupied home perfect for the next candidate. Secondary cavity nesters of the avian variety range from tiny Saw Whet owls, Chestnut-Backed chickadees, nuthatches, creepers, wrens and Tree swallows to larger kestrels, Wood ducks and even Great Horned owls. The list goes on and on when discussing the birds who take advantage of cavities made by others.
Swan Lake Christmas Hill Nature Sanctuary is lucky enough to host an abundance of Wildlife Trees that provide ample opportunity for exploration. My personal favorite? Woodpecker Castle! Nestled in the field just North East of the lake, this Swan Lake gem can be found if you follow the trail from the Nature House clockwise. Once you emerge from the trees and take in the view of what was previously used as farmland, you will notice a lone dead Douglas fir piercing the landscape. This palace is Woodpecker Castle.
While I don’t always see the activity that is constantly happening at Woodpecker Castle, I always love to stop with groups of visitors and take a few minutes to dive into the importance of Wildlife Trees. On Vancouver Island there are several of our fellow mammals, some endangered, that also rely on Wildlife Trees. Many of our Island bat species, such as the darling Little Brown bat and the regal Hoary bat use these Wildlife Trees as roosts. These havens provide a safe place for our local vampire hunters to rest during the day, before they spend parts of the night feasting on pesky blood-sucking mosquitos. The Little Brown bat is recorded to eat up to 1,000 insects per hour so they certainly need uninterrupted sleep during the day!
Another charismatic mammal that frequently calls Wildlife Trees their home are mama raccoons with their kits. While her kits are still too small to go on scavenging missions, mama raccoon needs to be sure her babies are kept in a safe place. Where is safer than a warm hovel in a dead tree?
During your next nature outing, I encourage you to look closely at what you may have previously regarded as a tree past their prime. Listen and you may be rewarded with the kingfisher like call of the Downy woodpecker, or the drumming of an opinionated Pileated woodpecker. Perhaps you will catch a flash of orange if you are still enough, and you will know you are in the presence of a Northern flicker. Wildlife Trees are full of more life than living trees, but they do require the viewer to look past their misleading exterior to be rewarded. Look closely, and your reward could be great!