Eating Invertebrates from Trees

     Several kinds of small, wintering woodland birds in the Middle Atlantic States, including two species of chickadees, tufted titmice, golden-crowned kinglets, two kinds of nuthatches, brown creepers, seven types of woodpeckers and two species of wrens, eat invertebrates from different parts of trees, thus reducing competition for that food among those birds.  Different groups of birds exploited unique niches on trees to get food, causing the development of different bird species in forests.  But, being adaptable, these birds also get food in woodlots, and older suburban areas with their many maturing trees.  And these birds are entertaining to us as each species gets food from a different part of every tree.
     The closely-related and nearly look-alike black capped and Carolina chickadees, titmice and kinglets flutter lightly among the tiny crevices of twigs and buds on trees in winter to find and eat invertebrates and/or their eggs.  The birds' little bodies and tiny, tweezer-like beaks allow them to feed the way they do.  These handsome birds fill a niche that larger birds could not, thus having it mostly to themselves.
     Permanent resident white-breasted nuthatches and wintering red-breasted nuthatches and creepers are attractive small birds that search for invertebrates and their eggs in crevices in tree bark.  The gray or brown upper part feathers of these birds camouflage them on tree trunks.
     Nuthatches are real acrobats, creeping up vertical tree trunks, and down them headfirst in their search for invertebrate food.  Nuthatches also cling and walk along the under sides of branches.  And they have stout, sharply-pointed bills for poking into cracks in bark to pull out invertebrates.
     Creepers travel along tree trunks differently than nuthatches.  Creepers flutter to the base of a large tree and slowly, jerkily hitch up the trunk in a spiral, all the while peeking into cracks in bark for invertebrates.  When satisfied with one tree, creepers flutter down to the bases of others and repeat their spiral climbs, all day, every day.  Creepers have stiff tail feathers to help hold them upright on vertical trunks and thin, curved-down bills for probing crevices for food.
     Having diverged from a common ancestor, all woodpecker species on earth, including the seven kinds in the Mid-Atlantic States in a year's time, have characteristics in common, including stiff tail feathers to help hold them erect on vertical tree trunks and feet with two toes in front and two in back to help them cling to tree trunks.  Woodpeckers chip away bark from trunks and limbs and chisel into the wood underneath.  Then they push their long, sticky tongues into invertebrate tunnels in the wood to snare those little critters and pull them out into their beaks to swallow.
     Permanent resident Carolina wrens and wintering winter wrens live among and get invertebrate food from fallen logs, brush piles and piles of leaves carpeting woodland floors and under planted shrubbery and log piles on maturing suburban lawns.  The feathers of wrens are brown, which blends them into their habitats of forest floors and older lawns.  To capture invertebrates through winter, they scurry like feathered mice among those sheltering niches.
     All these attractive, wintering birds eat invertebrates from various parts of trees, each kind in its own way, in its own niche, which reduces rivalry for food.  Every species on Earth has its particular niche that it evolved in, a niche that suits its needs better than any other species.