The bluebirds are a group of medium-sized, mostly insectivorous or omnivorous bird

Bird

Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s in the genus Sialia of the thrush

Thrush (bird)

The thrushes, family Turdidae, are a group of passerine birds that occur worldwide.-Characteristics:Thrushes are plump, soft-plumaged, small to medium-sized birds, inhabiting wooded areas, and often feed on the ground or eat small fruit. The smallest thrush may be the Forest Rock-thrush, at and...

 family (Turdidae). Bluebirds are one of the few thrush genera in the Americas

Americas

The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...

. They have blue, or blue and red, plumage. Female birds are less brightly colored than males, although color patterns are similar and there is no noticeable difference in size between sexes.

Species:

• Eastern Bluebird
  Eastern Bluebird
  The Eastern Bluebird, Sialia sialis, is a small thrush found in open woodlands, farmlands and orchards, and most recently can be spotted in suburban areas. It is the state bird of Missouri and New York....
  
  , Sialia sialis
• Western Bluebird
  Western Bluebird
  The Western Bluebird is a small thrush, approximately to in length.Adult males are bright blue on top and on the throat with an orange breast and sides, a brownish patch on back, and a gray belly and undertail coverts. Adult females have a duller blue body, wings, and tail than the male, a gray...
  
  , Sialia mexicana
• Mountain Bluebird
  Mountain Bluebird
  The Mountain Bluebird is a medium-sized bird weighing about 2-5 ounces, with a length from 15–20 cm . They have light underbellies and black eyes. Adult males have thin bills are bright turquoise-blue and somewhat lighter beneath. Adult females have duller blue wings and tail, grey breast,...
  
  , Sialia currucoides

Bluebirds are territorial, prefer open grassland with scattered trees and are cavity nesters (similar to many species of woodpecker

Woodpecker

Woodpeckers are near passerine birds of the order Piciformes. They are one subfamily in the family Picidae, which also includes the piculets and wrynecks. They are found worldwide and include about 180 species....

).