Warblers are colourful small birds, playing an important role for North American forests. They feed on destructive insects, mainly caterpillars, foraging over the trees, at different levels in the forest. Some species forage in lower branches or bushes, others at mid levels, on trunk and branches, and others in the canopy, among foliage or needles.
These birds generally have musical songs, but almost all these populations utter a dry «chip». This call is very distinctive of the family.
Warblers are very different in plumage, displaying bright colours, with females duller than males. Behaviour shows some similar attitudes, but every species keeps specific habits.
Reproduction and nesting also present differences. Some warbler's nests are located on or near the ground, other nests at some height, close to the trunk or in the outer branches, but, except two species nesting in cavities, all the others build open cup-shaped nests, very compact and well concealed into tangles of vines, bushes or foliage and needles.
Generally, female builds the nest and incubates the eggs, but both parents feed the altricial young. They fledge at about 8 to 12 days after hatching.
Warblers feed primarily on insects, but they also eat some berries and fruits, and flower nectar.
North American warblers winter in tropical forests, in Central America, northern of South America, and islands.
Warblers are declining in some parts of their range, with the forest fragmentation, and parasitism by Brown-headed cowbird.
Photographs by Alfredo Colón
Text by Nicole Bouglouan
Same sources as in cards