The family Sylviidae includes 14 species found in North America.

Old World Warblers are found in grass, thickets, reedbeds, marshes, swamps, thickets, grass, usually near water. They occur in Eurasia, Africa, Arabia, Japan, Philippines, southern Pacific islands and Australia.

They are 12-19 cm. in size. Food is primarily insects. The nest is a deep cup of plant material, cobwebs, often attached to several reeds over water or hanging from several twigs in a bush, thicket or similar sites. Eggs usually 4-6, variable; pinkish, whitish, greenish with reddish, yellowish, gray to black spots/blotches.

Gnatcatchers are small (10-11 cm) and slender with long tails and medium-length bills. Four species occur in North America. Colors are mostly bluish-gray above, white or grayish below. Tails are black with white outer feathers. Some have black crowns or black mask. They feed on insects and spiders. 

The nest is a small, neat cup of soft plant fibers camouflaged with lichens, bits of moss, fastened with cobwebs to a horizontal branch, in a tree fork or bush. Eggs 2-3 in tropics, 4-5 in temperate areas, bluish to white, speckled with reddish-brown.