Nesotriccus ridgwayi
The Cocos Tyrannulet, *Nesotriccus ridgwayi*, is a small, unassuming yet critically important passerine, the sole landbird endemic to Costa Rica's remote Cocos Island. Measuring approximately 11.5-13 cm (4.5-5.1 in) in length and weighing around 8-11 grams, its physical appearance is notably drab, featuring olive-green upperparts, a dull whitish throat and chest, and a pale yellowish wash on the belly and undertail coverts. Subtle pale wing-bars are often present, and it exhibits a relatively...
This tyrannulet exclusively inhabits the humid tropical broadleaf forests and dense undergrowth of Cocos Island, ranging from sea level up to the highest elevations of the island.
Primarily insectivorous, their diet consists of a variety of small arthropods, including beetles, flies, caterpillars, and spiders, which they glean from foliage or capture in flight.
Cocos Tyrannulets are diurnal, exhibiting active foraging throughout the day, often moving with a distinctive mouse-like quickness through the dense lower and mid-story vegetation. Their primary foraging strategy is sally-gleaning, involving short, agile flights to snatch insects directly from le...
The Cocos Tyrannulet is strictly endemic to Cocos Island (Isla del Coco), an isolated oceanic island belonging to Costa Rica, located approximately 550 km (340 mi) southwest of the Costa Rican mainland in the Pacific Ocean. Its entire global range is confined to this single, relatively small land...
Critically Endangered
- The Cocos Tyrannulet is the ONLY land bird species truly endemic to Cocos Island, making it a unique evolutionary treasure. - Despite its drab appearance, it is considered a 'flagship species' for the conservation of Cocos Island's unique ecosystem. - Its genus name, *Nesotriccus*, literally tr...