Bird of the Month - September 2006
Reinita del Bosque Enano (Dendroica angelae)
Name in English: Elfin-woods Warbler
The Elfin-woods Warbler is a rare endemic bird species only found in upland forests in Puerto Rico. It is globally threatened, listed as an endangered species candidate by the U.S. Fish and Wildlife Service and considered vulnerable by the Puerto Rican Department of Natural and Environmental Resources and BirdLife International.
- Adult: A small bird with black and white plumage, thin white eyebrow stripe, black crown, white patches on ear coverts and neck, and a prominent white eye ring. It has a blackish bill, dark bluish-gray legs, two white wing bars and two white spots in the outer tail feathers. Under parts are white, with black streaks on the throat, breast and flanks. Also has a long bill and relatively short rounded wings, both characteristics of island species. Sexes are alike but males tend to have larger amounts of black streaking on the breast and throat (Delannoy, pers. com.).
- Current threat to Elfin-woods Warbler habitat is continued development of mountain peaks for communication infrastructure and roads, which causes destruction, fragmentation, and alteration of high elevation habitats.
- Puerto Rico’s current urban sprawl makes it difficult for this species to move from one end of the island to the other and probably prevents gene flow between the populations.
- Natural disasters, such as hurricanes, pose a threat to Elfin-woods Warbler habitat and can affect its population size and distribution.
- Dendroica angelae was named after Mrs. Angela Kepler, one of the species discoverers.
- The common name refers to the place where the species was discovered as well as, to its size. In Puerto Rico most people call small birds “Reinita” and “del Bosque Enano” refers to the dwarf forest where it was seen for the first time.
- Current populations of the species are almost 100 km apart.
- Recent surveys show the species is no longer present in previously reported areas of the Carite and Toro Negro Forests, formerly part of its historical range. This critical finding reduces the species’ limited range even more, threatening its long-term existence.
Where to find more information?
Anadón-Irizarry, V. 2006. Distribution, Habitat Occupancy and Population Density of the Elfin-Woods Warbler (Dendroica angelae) in Puerto Rico. M.S. Thesis, University of Puerto Rico, Mayagüez, 64 pp. Download thesis (PDF, 1.9 MB) See list of references, pages 37-39.
BirdLife International (2006) Species factsheet: Dendroica angelae
Sociedad Ornitológica Puertorriqueña, Inc. (2006). Información sobre las aves endémicas de Puerto Rico: Reinita del Bosque Enano.
Elfin-woods Warbler Bird of the Month contributed by Veronica Anadón, Carlos A. Delannoy, Ph.D., and Adrianne G. Tossas, Ph.D
Cameron and Angela Kepler discovered the species in 1968 while conducting research on the Puerto Rican Tody (Todus mexicanus) and the Puerto Rican Parrot (Amazona vittata) in the Caribbean National Forest in eastern Puerto Rico. It was the first new species to be described from the West Indies since 1927, and the first in Puerto Rico in the Twentieth Century.
- Juvenile: Immature birds have greenish plumage, molting lasts almost a year. First-year birds have olive-green head, yellowish eye ring, upperparts with yellowish wing bars and tertial spots, pale yellowish-olive underparts with dusky olive streaks.
- Song comprises a series of short, rapidly uttered, unmusical notes on one pitch, increasing in volume and ending with a short series of distinct double notes. Also produces a short metallic “chip” call and a contact call which is similar to the song but without the double-note ending.
- Feeds on insects, mostly in the canopy, gleans very actively from leaves and small branches. Also joins mixed-species flocks while foraging.
- Breeding occurs between March and June.
- Nests have been found placed in trees among leaf-litter trapped in vegetation or vines at heights between 1.3-7.6 m, one nest was found in a tree cavity.
- Nests can contain broods of up to four nestlings.
Range and Habitat Needs
- Endemic to Puerto Rico where is is uncommon and local.
- Found only in mountain forests: El Yunque (Caribbean National Forest) in Sierra de Luquillo, the Carite State Forest in the Sierra de Cayey, and Toro Negro and Maricao State Forests in the Cordillera Central.
- According to a recent population survey (2003), the species is only found in El Yunque and the Maricao State Forest.
- Had an aggregated spatial distribution and was more abundant in Podocarpus type forest in Maricao, and Palo Colorado and Dwarf Forest in El Yunque.
- Considered threatened due to its limited habitat.
- Dr. Carlos Delannoy and students from the University of Puerto Rico, Mayagüez Campus have been studying the Maricao population since 2003. The group has established the Elfin-woods Warbler distribution and is trying to determine the influence of vegetation structure on its distribution. Elfin-woods Warblers have been found beyond the forest boundaries in private fincas and coffee plantations.
- The Department of Natural and Environmental Resources and the community-based grassroots group Casa Pueblo have introduced an initiative for a central corridor in the Cordillera Central. The objective is to join central protected areas by a wide corridor of forested land which will aid movements of species between protected areas. If extended eastward towards the Luquillo Forest this corridor could promote the dispersion of Elfin-woods Warblers.