- 4.7–5.5 in
- 7.9 in
- 0.3–0.5 oz
- Moucherolle tchébec (French)
- Mosquerito mínimo, Tontín chebec (Spanish)
- Unlike most species of songbird, adult Least Flycatchers migrate to their wintering grounds before molting, while young birds molt before and during autumn migration. Why such a pattern has developed remains unclear, but it may result from strong selection on adults for early arrival and establishment of territories on the wintering grounds.
- One Least Flycatcher nest was found to have used dragonfly wings as nest lining.
- The oldest recorded Least Flycatcher was at least 8 years old when it was recaptured and rereleased during banding operations in Virginia.
Breeds in semi-open woodlands, orchards, and shrubby fields. Winters along wooded ravines, woodland edge, and brushland.
Mostly insects, some fruit in winter.
- Egg Description
- Yellowish or creamy white, unmarked.
- Condition at Hatching
- Helpless and with only small patches of down.
Neat open cup woven of bark strips, grass, caterpillar webs, lichens, hair, feathers, rootlets, mosses, and other bits of vegetation; lined with fine grasses, feathers, hair, down, and plant stems; placed in crotch or fork of small tree.
Captures insects by hawking and hover-gleaning.
Least Flycatcher populations declined by about 58% between 1966 and 2015, according to the North American Breeding Bird Survey. Partners in Flight estimates a global breeding population of 36 million with 12% spending some part of the year in the U.S., 62% in Mexico and 88% breeding in Canada. The species rates a 10 out of 20 on the Continental Concern Score and is not on the 2016 State of North America's Birds' Watch List.