House SparrowThe house sparrow was brought to America from Europe in hopes of controlling insects. As it turns out, it prefers seeds to insects and has become a pest. House sparrows (sometimes called English sparrows) compete with many native birds for nesting cavities and bird nesting boxes.
Black-Capped Chickadee and Carolina ChickadeeInfluential conservationist Aldo Leopold noticed that the chickadees in his forest “investigate every loud noise.” He surmised that, for them, nature’s “dinner bell” was the crash of falling old trees, which present these perky insectivores with thousands of insect eggs and pupae.