Costa Rica’s south Pacific coast is home to over 400 bird species. About a dozen of these species are endemic, restricted to this region and adjacent Panama. These regional endemics include four species of conservation concern, which inhabit the lush tropical forests and coastal mangroves along the Osa Peninsula. These are:
- the Mangrove Hummingbird,
- Yellow-billed Cotinga,
- Turquoise Cotinga, and
- Black-cheeked Ant-Tanager.
In addition, to these endemic birds, the Osa Peninsula supports one of the healthiest populations of Scarlet Macaws in Central America. Migrant shorebirds and songbirds from North America use the Osa Peninsula during northern winters. Neotropical migrants include the U.S. WatchListed Olive-sided Flycatcher, Wood Thrush, Golden-winged Warbler, Kentucky Warbler, Prothonotary Warbler, and Canada Warbler. WatchListed shorebirds occurring here include the Snowy Plover, Wilson’s Plover, American Golden-Plover, Marbled Godwit, Wandering Tattler, Surfbird, Red Knot, Sanderling, Semipalmated Sandpiper, Western Sandpiper, White-rumped Sandpiper, and Stilt Sandpiper.
Mangrove Hummingbird (Amazilia boucardi)
The Mangrove Hummingbird is an endangered species endemic to Costa Rica’s Pacific coast, where it occurs mainly in mangroves. Although mangroves are protected by law in Costa Rica, mangroves harboring this species continue to be cleared for shrimp farms and coastal development, such as the mangroves in Puerto Jimenez.
 
A female Mangrove Hummingbird photographed in mangroves near Sandalo, Osa Peninsula. Males show blue plumage in their throat and breast. The white tips on the outer tail feathers offer a good field mark for this species. (Photos by Daniel Lebbin/American Bird Conservancy).
Yellow-billed Cotinga (Carpodectes antoniae)
Male Yellow-billed Cotingas have dove-like proportions and are adorned with almost pure white plumage. They seem like a symbol of peace as they forage for fruit high in the forest canopy alongside other cotingas, tityras, toucans, and other birds. During the breeding season, males perform a swooping flight display. The Yellow-billed Cotinga is an endangered species endemic to Costa Rica’s Pacific coast and adjacent westernmost Panama. Little is known about their population distributions or seasonal movements. They are thought to breed within mangroves, and wander widely through forests after breeding. The mangroves of the northern Osa Peninsula are thought to be a stronghold for this species, but recent surveys are demonstrating that the nearby forests provide critical foraging areas for these birds.
 
The adult male Yellow-billed Cotinga is almost pure white (left). Females are mostly ashy gray, with subadult males (right) intermediate. These birds were photographed where mangroves meet mature forests at Rincón, Osa Peninsula. (Photo on the left by Ulisis Quintero Hernandez; photo on the right by Daniel Lebbin/American Bird Conservancy).
Turquoise Cotinga (Cotinga ridgwayi)
 Few birds are as brilliantly colored as an adult male Turquoise Cotinga. This species forages high in the forest canopy for fruits. The Turquoise Cotinga is endemic to Costa Rica’s south Pacific slope and adjacent westernmost Panama. Most of its habitat in Panama has already destroyed. Its conservation status is listed as vulnerable by BirdLife International, though its threat level may deserve upgrading to endangered. It is thought to make seasonal movements, but little is known about this behavior despite important implications for protecting forests throughout potential migratory routes.
Adult male Turquoise Cotingas are decorated with sky blue and deep violet plumage, whereas females are clad in drabber tones. This individual was photographed at Rincón, Osa Peninsula. (Photo by Daniel Lebbin/American Bird Conservancy).
Black-cheeked Ant-Tanager (Habia atrimaxillaris)
This skulking tanager alerts the observer to its presence with noisy contact calls and harsh chatter. During the breeding season, it sings a repeated series of whistles at dawn. You can listen to recordings of this species online at the Macaulay Library. The Black-cheeked Ant-Tanager is an endangered species, restricted to forests of the Osa Peninsula and Golfo Dulce in Costa Rica. It also qualifies as an Alliance for Zero Extinction trigger species. Much of its habitat outside the Osa Peninsula in the Golfo Dulce region has been destroyed.
 
Black-cheeked Ant-Tanager, photographed at Bosque del Rio Tigre Lodge (www.osaadventures.com), Osa Peninsula. (Photos by Daniel Lebbin/American Bird Conservancy).
FOO Bird Conservation and Research Activities
Friends of the Osa is spearheading efforts with a network of partners to conserve birds in the region through research, habitat stewardship, and educational programs.
Our most recent research efforts include an ongoing study, initiated in December 2007, on the distribution and ecology of the Yellow-billed Cotinga and other endemic birds of conservation concern in the Osa region. This project is not yet complete, but already recording important observations of Yellow-billed Cotinga at previously unsurveyed locations as well as unknown foraging and breeding behaviors.
Because the primary threat to birds in the Osa Peninsula is the loss and fragmentation of their habitats, Friends of the Osa is helping to protect and restore habitats in the region through land acquisition, habitat restoration, and local education programs. Friends of the Osa acquired 2,800 acres of forested land, where the Osa Biodiversity Center is located. In 2008, FOO acquired an additional 1,500 acres adjacent to this property at Cerro Osa, which includes primary forest and a teak plantation which will be used to experimentally study processes of forest restoration. These forests are part of the Matapalo Conservation Corridor on the Osa Peninsula.
In late 2007, FOO trained and partnered with local bird tour leaders Abraham Gallo and Liz Jones of Bosque del Rio Tigre Lodge to conduct surveys of endemic birds in the region. Since then, this collaboration has expanded to other lodges, bird guides, and local people.
If you would like to support our efforts in bird conservation, you can donate online here and indicate that you would like to support Friends of the Osa's Bird conservation and research projects. |
