Empidonax alnorum
The Alder Flycatcher (Empidonax alnorum) is a small, enigmatic New World flycatcher, renowned for its challenging visual identification among birders. Measuring 12-16 cm (5-6.3 in) in length and weighing 8-14 g (0.28-0.49 oz), it sports a drab olive-greenish back, whitish underparts often with a faint yellowish wash, and two indistinct pale wing bars. A key field mark is its large, often faint, grayish eye-ring, which tends to be less prominent than that of its near-identical sibling species,...
This species primarily inhabits moist, shrubby deciduous or mixed-wood environments, particularly along beaver ponds, stream edges, and forest clearings within boreal and northern temperate zones. During winter, it favors tropical lowland forests, often near water.
Primarily insectivorous, their diet consists mainly of flies, wasps, bees, beetles, moths, and caterpillars, supplemented with spiders and occasionally small berries in late summer or fall. They forage predominantly by aerial hawking, capturing insects in flight.
Alder Flycatchers are diurnal insectivores, typically observed perched upright on an exposed branch, twitching their tails subtly. They employ a 'hawk-sallying' foraging strategy, launching from a perch to snatch flying insects in mid-air, occasionally gleaning prey from foliage. Males are highly...
The Alder Flycatcher breeds across a vast expanse of boreal North America, extending from central Alaska, throughout Canada, eastward to Newfoundland, and south into the northernmost US states. In the United States, breeding occurs in parts of New England, the Great Lakes region, and discontinuou...
Least Concern
- The Alder Flycatcher and Willow Flycatcher were once considered a single species known as "Traill's Flycatcher" until scientists discovered consistent vocal differences. - Unlike most Empidonax flycatchers, their songs are the most reliable, and often the *only*, way to differentiate them visua...