Oilbirds are one of the strangest species of birds. They look kind of like nightjars (another strange bunch) but instead of zooming around in the darkness in pursuit of moths, the Oilbird ventures into the night to pluck fruits from rainforest trees in hovering flight. Daylight hours are passed away in caves or dark, cave-like ravines where they make all sorts of bizarre snarling noises related to being an “alternative bird” and clicking sounds associated with echolocation. Unlike nightjars, the bill is hooked rather like that of a parrot and the youngsters are so fat that (like some petrels and storm-petrels) they were historically boiled down for their oil in some areas of their South American range! Although the huge monocultures of palm, soy, and corn majorly suck, at least there is no longer any excuse for boiling down an Oilbird!
Oilbirds are so darn oily because they love to eat oily fruits from palms and wild avocados from Lauraceaeous trees. While they can fly up to 25 miles from their nests during the breeding season, they can apparently go a lot further once their fledglings take wing. By “a lot further”, I mean all the way to Monteverde, Costa Rica from northern South America!
Recently, guides in the Monteverde area found Oilbirds that were foraging on fruiting trees located on trails owned by the Hotel Fonda Vela and dozens of people have gone to see them flutter around in the cloud forest canopy. The Oilbird was already on the Costa Rican list but very few people have actually laid eyes upon a live one when birding Costa Rica. Remains have been found on Cerro de la Muerte, and there have been reports of perched birds from Ensenada and the Osa Peninsula but to my knowledge, this is the first time that the species has been “staked out” in Costa Rica. Who knows how long they will stay, but if you are headed to Monteverde anytime soon, make sure to ask local guides about these strange vagrants!
Although I can’t discount the possibility that a small colony is breeding in some inaccessible cave or ravine in Costa Rica,I think it’s more likely that Oilbirds in Costa Rica are casual migrants from Colombia (nearest known breeding sites) or from unknown breeding sites in Panama. I am sure that most escape detection in Costa Rica due to their nocturnal behavior, they would still be detected on a more regular basis if they were breeding in the country because there are so many guided night hikes taking place. I doubt I will get up to Monteverde anytime soon but at least I can hope that an Oilbird will visit Quebrada Gonzalez and perch where I can see it.