By Kelly Koch
MONTEVERDE, Costa Rica — Two shrill whistles followed by a mechanical bonk ring high in the crown of the Costa Rican cloud forest. This is the three-wattled bellbird sounding the alarm for conservation in Costa Rica.
The bellbird is named for the male’s three fleshy “wattles” that hang from the top of its bill and on either side of its mouth.
The strange adornments are often misidentified as partially consumed worms, said naturalist Victorino Molina Rojas, one of the founders of the Bellbird Biological Corridor project.
But the bellbird does not eat worms, Molina said. Instead, they enjoy wild avocado, which is found throughout the bird’s range.
The bellbird’s range includes the cloud forests of Monteverde, at 1,600 meters in elevation, and stretches west, down to the mangrove coastline of the Gulf of Nicoya.
The mature male bellbird is mostly chestnut brown, which contrasts nicely with a stark white head and neck. Female and immature male bellbirds are designed for camouflage, Molina said; dull yellow feathers with brown streaks help the birds blend into the forest.
Nesting habitat is crucial for the endangered bellbird because it only lays one or two eggs per season.
Bellbirds are secretive nesters. Molia explained that the simple nest of twigs is rarely seen because it is well hidden in thick patches of vegetation.
The plump birds participate in awkward confrontation to defend the best perches. Singing from the highest branch helps the bellbird’s mating call broadcast up to a kilometer away, Molina said.
Intruding birds bump competitors toward the end of a branch. The most persistent bird will dismiss the loser with a mocking bonk.
Molina said the older and more handsome males are most likely to attract a female. It can take up to seven years before the male bellbirds display mature plumage.
The bellbird is threatened by habitat loss, Molina said. The Pacific slopes of Costa Rica have been heavily deforested to make room for agricultural crops and cattle.
The three-wattled bellbird is the icon for the corridor project, led by Evelyn Casares Cespedes, president of the Costa Rican Conservation Foundation. The goal of the corridor is to connect existing patches of forest to form a cohesive migration path for the bellbird.
Protecting existing forest and planting new trees are beneficial for all forms of life in and around the biological corridor, Casares said. Insects, mammals and reptiles also gain habitat from the corridor.
Tourism is a main driver of the Costa Rican economy, and preserving the bellbird supports the ecotourism industry. Birders from around the world flock to the Monteverde area to catch a glimpse of or hear the pleading song of the bellbird.