Nestled amidst the lush greenery of Costa Rica’s mountains, the Alder Flycatcher (Empidonax alnorum) presents a delightful challenge for even the most seasoned birdwatcher. This small, olive-brown songbird, with its subtle markings and penchant for staying hidden, is a true master of camouflage. But with a keen eye and a bit of patience, you might just be rewarded with a glimpse of this fascinating creature.
Description and Identification:
The Alder Flycatcher is a medium-sized member of the tyrant flycatcher family, measuring around 5-7 inches in length. Its upperparts are a muted olive-green, while its underparts are a pale yellow, with a hint of olive on the sides. A distinguishing feature is the thin white eye ring, adding a touch of brightness to its face.
Identifying this flycatcher can be tricky, as it’s very similar to other Empidonax species, particularly the Willow Flycatcher. However, there are a few key differences:
- Size: The Alder Flycatcher is slightly smaller than the Willow Flycatcher.
- Tail Flicking: The Alder Flycatcher has a characteristic habit of flicking its tail upwards, a behavior not typically seen in the Willow Flycatcher.
- Vocalizations: While both species have similar songs, the Alder Flycatcher’s song is often described as a rolling “freeBEER,” while the Willow Flycatcher’s call is a sharp “tsit.”
Habitat and Distribution:
The Alder Flycatcher prefers open areas with scattered trees, such as clearings, edges of forests, and even parks and gardens. In Costa Rica, you’re most likely to encounter them in the Central Valley region, particularly at higher elevations. They are also found in other mountainous areas throughout the country.
Behavior and Diet:
These flycatchers are active insectivores, spending their days perched on branches, scanning for flying insects. Their sharp vision and quick reflexes make them adept hunters, snapping up mosquitoes, flies, and other small prey in mid-air.
Nesting and Breeding:
Alder Flycatchers typically build their nests in trees or shrubs, constructing a cup-shaped structure from twigs, leaves, and moss. Breeding season in Costa Rica occurs between March and August, with the female laying 2-3 eggs.
Tips for Seeing Alder Flycatchers:
- Listen carefully: Their distinctive calls and songs are often the first clue to their presence.
- Focus on edges and clearings: Scan the edges of forests, parks, and gardens, where they are most likely to be perched.
- Be patient: These birds can be quite shy, so it may take some time and observation to spot them.
A Rewarding Encounter:
While the Alder Flycatcher may be a challenge to identify, the satisfaction of spotting one is truly rewarding. Their subtle beauty and secretive nature add a layer of intrigue to the birding experience in Costa Rica’s mountains. So, keep your eyes peeled and your ears tuned, and you might just be lucky enough to catch a glimpse of this fascinating little flycatcher.
For more information, please view our comprehensive guide about the birds of Costa Rica
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