Chimney swifts are very small birds with adults only weighing about 1 ounce, and growing in length to be about 5 ½ inches. They are a dark grayish-brown in color with the feathers on their throat being slightly lighter in color. They have a slender cylindrical shaped body and very distinctive looking narrow, curved wings. Chimney swifts have a round head, very short neck, legs and tail, and a beak that is so short and wide that it almost appears non-existent. These birds are often described as a “cigar” with wings.
Chimney swifts live for about 4-5 years and generally mate for life. Their nests are made from twigs, leaves, mud, and saliva. They stick their nests to the vertical surface of structures, mostly choosing chimneys. The female will lay 4-5 eggs and the young will hatch from the eggs after about 19 days. About a month after hatching, they will fly from the nest.