Effects on bird abundance and diversity North American beaver

canada goose nest on beaver lodge

beavers waterfowl creating increased areas of water, , in northerly latitudes, thaw areas of open water, allowing earlier nesting season. in study of wyoming streams , rivers, watercourses beavers had 75-fold more ducks without.

trumpeter swans (cygnus buccinator) , canada geese (branta canadensis) depend on beaver lodges nesting sites. canada s small trumpeter swan population observed not nest on large lakes, preferring instead nest on smaller lakes , ponds associated beaver activity.

beavers may benefit birds frequenting ponds in several additional ways. removal of pondside trees beavers increases density , height of grass–forb–shrub layer, enhances waterfowl nesting cover adjacent ponds. both forest gaps trees had been felled beavers , gradual edge described complex transition pond forest intermixed grasses, forbs, saplings, , shrubs associated greater migratory bird species richness , abundance. coppicing of waterside willows , cottonwoods beavers leads dense shoot production provides important cover birds , insects on feed. widening of riparian terrace alongside streams associated beaver dams , has been shown increase riparian bird abundance , diversity, impact may important in semiarid climates.

as trees drowned rising beaver impoundments, become ideal nesting sites woodpeckers, carve cavities attract many other bird species, including flycatchers (empidonax spp.), tree swallows (tachycineta bicolor), tits (paridae spp.), wood ducks (aix sponsa), goldeneyes (bucephala spp.), mergansers (mergus spp.), owls (tytonidae, strigidae) , american kestrels (falco sparverius). piscivores, including herons (ardea spp.), grebes (podicipedidae), cormorants (phalacrocorax ssp.), american bitterns (botaurus lentiginosa), great egret (ardea alba), snowy egret (egretta thula), mergansers, , belted kingfishers (megaceryle alcyon), use beaver ponds fishing. hooded mergansers (lophodytes cucullatus), green heron (butorides virescens), great blue heron (ardea herodias) , belted kingfisher appeared more in new york wetlands beaver active @ sites no beaver activity.

by perennializing streams in arid deserts, beavers can create habitat increases abundance , diversity of riparian-dependent species. example, such upper san pedro river in southeastern arizona, reintroduced beavers have created willow , pool habitat has extended range of endangered southwestern willow flycatcher (empidonax trailii extimus) southernmost verifiable nest recorded in 2005.