"Fitting In" Narrative

The old growth forest is crowded with animal specialists. Some feed on special things. Some feed in special places. Some nest in unusual places. Some feed or nest at unusual times. The specialists follow one rule: no two species does exactly the same thing for a living.

All of us have a habitat, the place we live, and a niche, our “job” in that place. The creatures of the old growth are no different. We have already learned about the pale plants- mycotrophs- with no chlorophyll. They feed from the fungi, who break down woody debris. The fungi also enable the live trees to live and grow by supplying nutrients to their roots. The mycotrophs stimulate fungus growth with chemicals in return for nutrients from the fungi. Even though specialists seem at first glance to be independent – minding their own business -- they need each other to make the entire system work.

The birds of the old growth are great examples. Consider the little “flying cigars,” the swifts. Despite high metabolism – they must eat all day or starve – the swifts live nearly 20 years. Swifts make their nests mostly from saliva. They sometimes even “hibernate” during bad weather, dropping their body temperatures as much as 50 degrees.

The Vaux’s Swift nests and roosts in huge standing hollow snags. They feed, mate, and even bathe (splashing water with their tail during a low swoop) in the air. Flying as fast as 200 miles per hour, they feed on insects very high above the old growth canopy.

Black Swifts, close cousins, feed lower than the Vaux’s, and they nest behind high waterfalls! They come back to the same nesting spot their entire lives. The waterfalls in and around Avalanche Creek are good spots to see them in the early morning and late evening.

Four kinds of chickadees call the W-GIPP home – the mountain, Chestnut-backed, Black-capped and Boreal. Chickadees also drop their body temperatures on winter nights, roosting in old woodpecker holes. Boreal Chickadees spend their time in the higher subalpine firs and spruce. Black-capped Chickadees prefer mixed-age woods. In the old growth, Chestnut-backed Chickadees reach their eastern limit in McDonald Creek Valley, for the same warm, moist reasons the cedars and hemlocks are here. They feed high in the canopies. Mountain Chickadees feed in the lower half of the old growth.

Brown Creepers land low on the trunk of large trees and spiral upward around the trunk as they feed. They prefer to nest behind a loose slab of bark on white pines, but because of the European disease white pine blister rust, have switched to hemlock bark.

Of the woodpeckers, Pileateds hammer large holes deep into the trees for ants. Hairy Woodpeckers dig medium depth, a small oval hole, and Downy Woodpeckers dig a shallow round hole. Black-backed Woodpeckers peel the bark of firs, looking for engraver beetle larvae, and Northern 3-toed Woodpeckers peel the bark from spruces.

Varied Thrushes, Winter Wrens and Rufous-sided Towhees feed on the ground. The thrushes prefer open understories, the wrens like hollow logs and the towhees like thickets.

Even though they specialize, some of these birds have an interesting cooperative feeding pattern. The larger woodpeckers dislodge insects for the bark feeders like nuthatches and creepers. They, in turn, expose smaller insects for the chickadees. They are followed by the ground-feeding thrushes. If you sit quietly in the old growth, these birds will eventually pass by in that order, feeding on the leavings of the previous birds.

Mammals are specialists, as well. Red-backed voles feed almost exclusively on the fungus inside of down logs. Red squirrels feed on seeds during the day and flying squirrels feed on lichens (like moss hanging from the branches) at night.

Pine martens, reddish members of the weasel family, chase down squirrels in trees. Their larger, darker cousin, the fisher, has mastered the art of flipping porcupines on their backs and eating them. Female fishers, only half the size of males, feed more on voles and hares. So, among fishers, there is even gender specialization.

In the old growth, everyone has their place and their job. Everyone needs everyone else, and the consequences of removing just one creature from the interwoven mix could send serious ripples through the entire community.

Last updated: February 24, 2015

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