Elfin-woods Warbler
Encyclopedia
The Elfin-woods Warbler (Dendroica angelae), or Reinita de Bosque Enano (Spanish name
), is a bird
endemic
to the Caribbean
island of Puerto Rico
where it is a local and uncommon species. Discovered in 1968 and described in 1972, it is the most recently described species of New World warbler
(Parulidae family). The species name, angelae, is a tribute to Angela Kepler
, one of its discoverers. An insectivore
, it feeds by gleaning
small insects off leaves.
Due to its small populations and restricted habitat
s, conservation efforts were begun in 1982 to protect this species but, as of 2005, the warbler was still in need of protection. The species is not in immediate danger as the majority of its habitat is protected forest
, but introduced species, such as rat
s and Small Asian Mongooses, habitat reduction, and natural disasters represent potential threats to the population.
genus of the New World warbler
family Parulidae. It was first observed in 1968 by Cameron and Angela Kepler
while they were conducting observations on two Puerto Rican endemic birds, the Puerto Rican Amazon and the Puerto Rican Tody
. On May 18, 1971, a specimen was captured in El Yunque National Forest
, which at the time was believed to be its only habitat. A year later Kepler and Parkes described and named the species making it the most recent warbler (Dendroica spp.) discovered in the New World. Also, it is the first species described in the Caribbean
since 1927 and the first Puerto Rican species described in the 20th century.
warblers (D. adelaidae
, D. delicata
, D. plumbea
and D. pharetra
), the species features a long bill
and short, round wing
s (53.8 mm (2.1 in) average). Among Dendroica spp., only D. adelaidae has a shorter wing length average (50 mm (2 in)) than the Elfin-woods Warbler. Juveniles differ from adults, retaining a grayish-green back for approximately a year and partially moulting from July to October. The Elfin-woods Warbler's average mature length is 12.5 cm (4.9 in) and its average weight is 8.4 g (0.296301281682941 oz). Sexual dimorphism
is not present in this species.
The Elfin-woods Warbler is often confused with the Black-and-white Warbler
(Mniotilta varia), a non-breeding species in the Caribbean occurring in Puerto Rico from mid-September to early May. The main physical distinction resides in the eyes. The Elfin-woods Warbler has an incomplete white eyering and the Black-and-white Warbler has a white band across the eye and a white lower half of the eyering. Another distinction is found in the crown, with the Elfin-woods's being entirely black and the Black-and-white's having a white band across.
s of the El Yunque National Forest in eastern Puerto Rico. The wind-clipped trees in these forests rarely exceed 5 metres (16.4 ft) height and are characterized by stiff, thick twigs, leathery leaves and impenetrable, dense undergrowth
ideal for hiding from predators. Three more populations were later discovered in the Maricao State Forest
(1972, largest known population), the Carite State Forest (1977) and the Toro Negro State Forest
(late 1970s). Also, studies showed that the species migrated
altitudinally to lower elevations, from 370 to 600 m (1,213.9 to 1,968.5 ft), tabonuco
and palo Colorado forests.
In September 1989, Hurricane Hugo
struck the central and eastern region of Puerto Rico affecting three (the El Yunque National Forest, Toro Negro and Carite populations) of the four known populations of the Elfin-woods Warbler. A survey conducted two years later in the Toro Negro Forest, located in the Cordillera Central
, did not find any individuals. Recent surveys suggest that, for reasons yet unknown, the populations at Carite and Toro Negro were likely extirpated
. Continued monitoring of the Elfin-woods Warbler populations is achieved through bird counts performed every 3 to 4 years by the Puerto Rican Breeding Bird Survey
(PRBBS). The last survey was conducted in 2001 in which 3 individuals were observed at the Maricao State Forest. IUCN's last assessment of the Elfin-woods Warbler, prepared in 2000, estimated a stable population
of 600 mature individuals.
Historically, the Elfin-woods Warbler was restricted to humid mountainous forests at four distinct locales in Puerto Rico. Presently, the species is presumed extirpated from two locales, occurring only at El Yunque National Forest and the Maricao State Forest. The elfin forest at El Yunque National Forest is characterized by high rainfall and humidity, low temperatures and insolation, and constant winds. It is found at mountain summits and is primarily composed of dense shrub and small trees with moss
and epiphyte
growth in its plants and floor. The species richness is low when compared to other types of forests (tabonuco, palo Colorado and palma sierra
forests) found in the Luquillo Mountains. The elfin forest at the Maricao State Forest, located in western Puerto Rico, receives an annual average rainfall of 2250 centimetres (885.8 in), a high amount considering that a rainforest, by definition, receives a minimum of 67 inches (1,701.8 mm) annually. However, since its soil has low water holding capacity its vegetation is more xeric than expected. The species's highest density occurs in Podocarpus
forests in the Maricao State Forest. Little information is available on the elfin forests at Toro Negro and Carite.
the middle canopy
for insects. While searching for food it often flocks with other birds, such as Black-and-white Warbler
s, Puerto Rican Tanager
s and Lesser Antillean Pewee
s. Three maneuvers used for catching prey, gleaning
, sally-hover and probing, have been described. Gleaning is described as a hunting maneuver made by a standing or moving bird. Sally-hover is a hunting maneuver made by a bird in flight. Probing is a maneuver in which the bird, by digging with its beak, forages the substrate looking for food in a manner similar to chickens. Gleaning, especially off leaves, is the maneuver used with more frequency by the Elfin-woods Warbler while probing is the least used.
The Elfin-woods Warbler's song
and call
are difficult to hear. The species has a subtle voice and its call and song resemble those of the Bananaquit
, the most abundant bird in Puerto Rico. The song is a series of "short, rapidly uttered, rather unmusical notes on one pitch, swelling in volume and terminating with a short series of distinct double syllables sounding slightly lower in pitch" while the call has been described as "a single, short, metallic chip".
The Elfin-woods Warbler breeds from March to June. Both parents are involved in the construction of the nest and in feeding the chicks. Nests are built close to the tree trunk
within dry aerial leaf litter, usually Cecropia
leaves (a material used by no other Parulidae species), in Bulbophyllum
wadsworthii
trees. Nests are well-concealed and located 1.3 to 7.6 m (4.3 to 24.9 ft) above ground level. Nests are cup-shaped and made from small root
s and twig
s, dry leaves of Chusquea
abietifolia and B. wadsworthii, and dry Panicum
maximum leaves. The interior is made from fibers of C. abietifolia, dry leaves and other plant matter
. Females lay 2 to 3 white colored eggs with red-brown spots. The chick's diet consists of insects – parents have been observed offering lepidoptera
n and orthoptera
n adults and lepidoptera
n larvae to hatchlings.
(Margarops fuscatus), the Puerto Rican Sharp-shinned Hawk
(Accipiter striatus venator) and the extirpated
White-necked Crow
(Corvus leucognaphalus) while unconfirmed native predators include two endemic snake
s and several carnivore
s (from fossil records
). Introduced species, such as cat
s (Felis domesticus), dog
s (Canis lupus familiaris), Black Rat
s (Rattus rattus) and Small Asian Mongooses (Herpestes javanicus) are also potential nest predators. These species have proliferated due to the presence of human-developed facilities, mainly for communication
purposes, in the Maricao State Forest and El Yunque National Forest. Two factors contribute to the destruction of the Elfin-woods Warbler's habitat, human
s and nature
. Human-related habitat destruction includes the construction of communication towers, acquisition of timber
, and expansion of roads and trails. Nature's contribution comes from natural disaster
s such as forest fire
s and hurricanes.
The Elfin-woods Warbler was placed on the United States federal candidate list for Endangered Species Act
in 1999 and the announcement was published on the Federal Register of 10/25/1999, Volume 64, No. 205, pages 57535-57547. The USFWS started to considered the need to protect the Elfin-woods Warbler in 1982. In 2005, a group of scientists, scholars, artists and environmentalists petitioned the Bush administration
to admit 225 species, among these the Elfin-woods Warbler, to the Endangered Species Act. Of these 225 species, more than one third have been on the candidate list for 20 or more years and half for 10 or more years. Recent studies also show that since the creation of the Endangered Species Act in 1973, 114 United States
species have become extinct
, many because of lack of habitat protection by the federal government.
The IUCN first evaluated the status of the Elfin-woods Warbler in 1988. At the time it was given a classification of lower Risk/least concern. In 1994, its status was changed to Lower Risk/near threatened and in 2000, its status was changed to vulnerable
, where it remains. The justification for maintaining the species' status as vulnerable is that "There are no direct or immediate threats, but the combination of a very small range and population may have important implications for its chances of long-term survival, and this species consequently qualifies as Vulnerable".
Spanish language
Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...
), is a bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
endemic
Endemism in birds
An endemic bird area is a region of the world that contains two or more restricted-range species, while a "secondary area" contains one or more restricted-range species. Both terms were devised by Birdlife International....
to the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
island of Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
where it is a local and uncommon species. Discovered in 1968 and described in 1972, it is the most recently described species of New World warbler
New World warbler
The New World warblers or wood-warblers are a group of small, often colorful, passerine birds restricted to the New World. They are not related to the Old World warblers or the Australian warblers....
(Parulidae family). The species name, angelae, is a tribute to Angela Kepler
Angela Kepler
Angela Kay Kepler is a New Zealand-born naturalist and author.She is a graduate of the University of Canterbury, New Zealand and has a Master’s degree from the University of Hawaii and a doctorate from Cornell University, New York. She also studied at Oxford University.She has conducted research...
, one of its discoverers. An insectivore
Insectivore
An insectivore is a type of carnivore with a diet that consists chiefly of insects and similar small creatures. An alternate term is entomophage, which also refers to the human practice of eating insects....
, it feeds by gleaning
Gleaning (birds)
Gleaning is a term for a feeding strategy by birds in which they catch invertebrate prey, mainly arthropods, by plucking them from foliage or the ground, from crevices such as rock faces and under the eaves of houses, or even, as in the case of ticks and lice, from living animals. This behavior is...
small insects off leaves.
Due to its small populations and restricted habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...
s, conservation efforts were begun in 1982 to protect this species but, as of 2005, the warbler was still in need of protection. The species is not in immediate danger as the majority of its habitat is protected forest
Forest protection
Forest protection is a general term describing methods purported to preserve or improve a forest threatened or affected by abuse. The types of abuse that forest protection seeks to prevent include:* Aggressive or unsustainable farming and logging...
, but introduced species, such as rat
Rat
Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...
s and Small Asian Mongooses, habitat reduction, and natural disasters represent potential threats to the population.
Discovery
The Elfin-woods Warbler is one of 29 species in the DendroicaDendroica
Dendroica is a genus of birds of the New World Warbler family Parulidae. It contains 29 species. The males in breeding plumage are often highly colorful...
genus of the New World warbler
New World warbler
The New World warblers or wood-warblers are a group of small, often colorful, passerine birds restricted to the New World. They are not related to the Old World warblers or the Australian warblers....
family Parulidae. It was first observed in 1968 by Cameron and Angela Kepler
Angela Kepler
Angela Kay Kepler is a New Zealand-born naturalist and author.She is a graduate of the University of Canterbury, New Zealand and has a Master’s degree from the University of Hawaii and a doctorate from Cornell University, New York. She also studied at Oxford University.She has conducted research...
while they were conducting observations on two Puerto Rican endemic birds, the Puerto Rican Amazon and the Puerto Rican Tody
Puerto Rican Tody
The Puerto Rican Tody is a tody endemic to the archipelago of Puerto Rico. Despite is scientific name, Todus mexicanus, it is endemic to Puerto Rico...
. On May 18, 1971, a specimen was captured in El Yunque National Forest
El Yunque National Forest
El Yunque National Forest, formerly known as the Luquillo National Forest, and the Caribbean National Forest, is a forest located in northeastern Puerto Rico. It is the only tropical rain forest in the United States...
, which at the time was believed to be its only habitat. A year later Kepler and Parkes described and named the species making it the most recent warbler (Dendroica spp.) discovered in the New World. Also, it is the first species described in the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
since 1927 and the first Puerto Rican species described in the 20th century.
Description
The Elfin-woods Warbler's upper body is predominantly black with white areas while its underparts are white with black streaks. Other identifying characteristics are dark brown eyes, white patches on its ears and neck, an incomplete white eyering, a white eyestripe, and two white spots on its outer tail feathers. Characteristic of AntilleanAntilles
The Antilles islands form the greater part of the West Indies in the Caribbean Sea. The Antilles are divided into two major groups: the "Greater Antilles" to the north and west, including the larger islands of Cuba, Jamaica, Hispaniola , and Puerto Rico; and the smaller "Lesser Antilles" on the...
warblers (D. adelaidae
Adelaide's Warbler
Adelaide's Warbler is a bird endemic to the archipelago of Puerto Rico belonging to the Dendroica genus of the Parulidae family. The species is named after Adelaide Swift, daughter of Robert Swift, the person who captured the first specimen.-Description:Dendroica adelaidae was originally...
, D. delicata
St Lucia Warbler
The St Lucia Warbler is a species of bird in the Parulidae family.It is endemic to Saint Lucia.-References:* BirdLife International 2004. . Downloaded on 25 July 2007....
, D. plumbea
Plumbeous Warbler
The Plumbeous Warbler is a species of bird in the Parulidae family.It is found only in Dominica and Guadeloupe.Its natural habitats are subtropical or tropical dry forests and subtropical or tropical moist lowland forests....
and D. pharetra
Arrowhead Warbler
The Arrowhead Warbler is a species of bird in the Parulidae family.It is endemic to Jamaica.Its natural habitat is subtropical or tropical moist montane forests.-References:* BirdLife International 2004....
), the species features a long bill
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
and short, round wing
Wing
A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...
s (53.8 mm (2.1 in) average). Among Dendroica spp., only D. adelaidae has a shorter wing length average (50 mm (2 in)) than the Elfin-woods Warbler. Juveniles differ from adults, retaining a grayish-green back for approximately a year and partially moulting from July to October. The Elfin-woods Warbler's average mature length is 12.5 cm (4.9 in) and its average weight is 8.4 g (0.296301281682941 oz). Sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
is not present in this species.
Black-and-white Warbler
The Black-and-white Warbler is a small New World warbler. It breeds in northern and eastern North America from southern Canada to Florida....
(Mniotilta varia), a non-breeding species in the Caribbean occurring in Puerto Rico from mid-September to early May. The main physical distinction resides in the eyes. The Elfin-woods Warbler has an incomplete white eyering and the Black-and-white Warbler has a white band across the eye and a white lower half of the eyering. Another distinction is found in the crown, with the Elfin-woods's being entirely black and the Black-and-white's having a white band across.
Population and distribution
When first discovered, the Elfin-woods Warbler was believed to exclusively occur in the high elevation, from 640 to 1030 m (2,099.7 to 3,379.3 ft), dwarf or elfin forestElfin forest
-Residential community:Elfin Forest is an unincorporated residential community of San Diego County in the foothills of the Santa Rosa Mountains. The quiet grouping of homes is southwest of Escondido and according to the USGS it is located at in the Escondido zip code of 92029...
s of the El Yunque National Forest in eastern Puerto Rico. The wind-clipped trees in these forests rarely exceed 5 metres (16.4 ft) height and are characterized by stiff, thick twigs, leathery leaves and impenetrable, dense undergrowth
Undergrowth
Undergrowth usually refers to the vegetation in a forest, which can obstruct passage through the forest. The height of undergrowth is usually considered to be 0.3 – 3 m . Undergrowth can also refer all vegetation in a forest, which isn't in the canopy....
ideal for hiding from predators. Three more populations were later discovered in the Maricao State Forest
Maricao State Forest
Maricao State Forest is located on the island of Puerto Rico, spread through the towns of San Germán, Sabana Grande and Maricao. It is commonly known as only the Monte del Estado, which refers to the mountain of that name located in the forest....
(1972, largest known population), the Carite State Forest (1977) and the Toro Negro State Forest
Toro Negro State Forest
Toro Negro State Forest is one of the 16 state forests in Puerto Rico. The forest is located in the central region of the island. The forest covers 6,945 cuerdas of mountains, with heights that include Cerro de Punta, the highest peak in the island...
(late 1970s). Also, studies showed that the species migrated
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
altitudinally to lower elevations, from 370 to 600 m (1,213.9 to 1,968.5 ft), tabonuco
Dacryodes excelsa
Dacryodes excelsa is a tree of the Caribbean region. Its vernacular names include tabonuco, gommier, and candlewood....
and palo Colorado forests.
Hurricane Hugo
Hurricane Hugo was a classical, destructive and rare Cape Verde-type hurricane which struck the Caribbean islands of Guadeloupe, Montserrat, St. Croix, Puerto Rico and the USA mainland in South Carolina as a Category 4 hurricane during September of the 1989 Atlantic hurricane season...
struck the central and eastern region of Puerto Rico affecting three (the El Yunque National Forest, Toro Negro and Carite populations) of the four known populations of the Elfin-woods Warbler. A survey conducted two years later in the Toro Negro Forest, located in the Cordillera Central
Cordillera Central, Puerto Rico
The Cordillera Central, or La Cordillera Central , is the main mountain range in Puerto Rico. Generally speaking, the range crosses the island from west to east with an average elevation of 915m and divides the territory's northern and southern coastal plains.La Cordillera Central runs east to...
, did not find any individuals. Recent surveys suggest that, for reasons yet unknown, the populations at Carite and Toro Negro were likely extirpated
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...
. Continued monitoring of the Elfin-woods Warbler populations is achieved through bird counts performed every 3 to 4 years by the Puerto Rican Breeding Bird Survey
Breeding Bird Survey
A breeding bird survey monitors the status and trends of bird populations. Data from the survey are an important source for the range maps found in field guides. The North American Breeding Bird Survey is a joint project of the United States Geological Survey and the Canadian Wildlife Service...
(PRBBS). The last survey was conducted in 2001 in which 3 individuals were observed at the Maricao State Forest. IUCN's last assessment of the Elfin-woods Warbler, prepared in 2000, estimated a stable population
Ecological stability
Ecological stability can refer to types of stability in a continuum ranging from resilience to constancy to persistence. The precise definition depends on the ecosystem in question, the variable or variables of interest, and the overall context...
of 600 mature individuals.
Historically, the Elfin-woods Warbler was restricted to humid mountainous forests at four distinct locales in Puerto Rico. Presently, the species is presumed extirpated from two locales, occurring only at El Yunque National Forest and the Maricao State Forest. The elfin forest at El Yunque National Forest is characterized by high rainfall and humidity, low temperatures and insolation, and constant winds. It is found at mountain summits and is primarily composed of dense shrub and small trees with moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
and epiphyte
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
growth in its plants and floor. The species richness is low when compared to other types of forests (tabonuco, palo Colorado and palma sierra
Prestoea
Prestoea is a genus of palms native to the Caribbean, Central and South America. Its ten species extends from Costa Rica and the Greater Antilles in the north to Brazil and Bolivia in the south....
forests) found in the Luquillo Mountains. The elfin forest at the Maricao State Forest, located in western Puerto Rico, receives an annual average rainfall of 2250 centimetres (885.8 in), a high amount considering that a rainforest, by definition, receives a minimum of 67 inches (1,701.8 mm) annually. However, since its soil has low water holding capacity its vegetation is more xeric than expected. The species's highest density occurs in Podocarpus
Podocarpus
Podocarpus is a genus of conifers, the most numerous and widely distributed of the podocarp family Podocarpaceae. The 105 species of Podocarpus are evergreen shrubs or trees from 1-25 m in height...
forests in the Maricao State Forest. Little information is available on the elfin forests at Toro Negro and Carite.
Diet and behavior
The Elfin-woods Warbler is commonly found foragingForaging
- Definitions and significance of foraging behavior :Foraging is the act of searching for and exploiting food resources. It affects an animal's fitness because it plays an important role in an animal's ability to survive and reproduce...
the middle canopy
Canopy (forest)
In biology, the canopy is the aboveground portion of a plant community or crop, formed by plant crowns.For forests, canopy also refers to the upper layer or habitat zone, formed by mature tree crowns and including other biological organisms .Sometimes the term canopy is used to refer to the extent...
for insects. While searching for food it often flocks with other birds, such as Black-and-white Warbler
Black-and-white Warbler
The Black-and-white Warbler is a small New World warbler. It breeds in northern and eastern North America from southern Canada to Florida....
s, Puerto Rican Tanager
Puerto Rican Tanager
The Puerto Rican Tanager is a small passerine bird endemic to the archipelago of Puerto Rico. It is the only member of the Nesospingus genus of the tanager family....
s and Lesser Antillean Pewee
Lesser Antillean Pewee
The Lesser Antillean Pewee is a species of bird in the Tyrannidae family.It is found in Dominica, Guadeloupe, Martinique, Puerto Rico, and Saint Lucia with records from Saint Kitts. Birds on Puerto Rico are sometimes considered to be a separate species The Lesser Antillean Pewee (Contopus...
s. Three maneuvers used for catching prey, gleaning
Gleaning (birds)
Gleaning is a term for a feeding strategy by birds in which they catch invertebrate prey, mainly arthropods, by plucking them from foliage or the ground, from crevices such as rock faces and under the eaves of houses, or even, as in the case of ticks and lice, from living animals. This behavior is...
, sally-hover and probing, have been described. Gleaning is described as a hunting maneuver made by a standing or moving bird. Sally-hover is a hunting maneuver made by a bird in flight. Probing is a maneuver in which the bird, by digging with its beak, forages the substrate looking for food in a manner similar to chickens. Gleaning, especially off leaves, is the maneuver used with more frequency by the Elfin-woods Warbler while probing is the least used.
The Elfin-woods Warbler's song
Bird song
Bird vocalization includes both bird calls and bird songs. In non-technical use, bird songs are the bird sounds that are melodious to the human ear. In ornithology and birding, songs are distinguished by function from calls.-Definition:The distinction between songs and calls is based upon...
and call
Bird song
Bird vocalization includes both bird calls and bird songs. In non-technical use, bird songs are the bird sounds that are melodious to the human ear. In ornithology and birding, songs are distinguished by function from calls.-Definition:The distinction between songs and calls is based upon...
are difficult to hear. The species has a subtle voice and its call and song resemble those of the Bananaquit
Bananaquit
The Bananaquit is a species of passerine bird of uncertain relation. It is tentatively placed in the tanager family, but classified as incertae sedis by other authorities such as the American Ornithologists' Union. Its classification is debated, and it is often placed in its own family: Coerebidae...
, the most abundant bird in Puerto Rico. The song is a series of "short, rapidly uttered, rather unmusical notes on one pitch, swelling in volume and terminating with a short series of distinct double syllables sounding slightly lower in pitch" while the call has been described as "a single, short, metallic chip".
The Elfin-woods Warbler breeds from March to June. Both parents are involved in the construction of the nest and in feeding the chicks. Nests are built close to the tree trunk
Trunk (botany)
In botany, trunk refers to the main wooden axis of a tree that supports the branches and is supported by and directly attached to the roots. The trunk is covered by the bark, which is an important diagnostic feature in tree identification, and which often differs markedly from the bottom of the...
within dry aerial leaf litter, usually Cecropia
Cecropia
Cecropia is a Neotropical genus presently consisting of sixty-one recognized species with a highly distinctive lineage of dioecious trees....
leaves (a material used by no other Parulidae species), in Bulbophyllum
Bulbophyllum
Bulbophyllum is the largest genus in the orchid family Orchidaceae. With more than 2,000 species, it is also one of the largest genera of flowering plants, exceeded only by Astragalus...
wadsworthii
Bulbophyllum wadsworthii
Bulbophyllum wadsworthii is a species of orchid in the genus Bulbophyllum.-References:**...
trees. Nests are well-concealed and located 1.3 to 7.6 m (4.3 to 24.9 ft) above ground level. Nests are cup-shaped and made from small root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...
s and twig
Twig
A twig is a small thin terminal branch of a woody plant. Twigs are critically important in identification of trees, shrubs and vines, especially in wintertime. The buds on the twig are an important diagnostic characteristic, as are the abscission scars where the leaves have fallen away...
s, dry leaves of Chusquea
Chusquea
Chusquea is a genus of bamboo with about 150 species. Most of them are mountain clumping bamboos native from southern Mexico to southern Chile and Argentina. They are sometimes referred to as South American mountain bamboos. Unlike most other bamboos, the stems of these species are solid, not hollow...
abietifolia and B. wadsworthii, and dry Panicum
Panicum
Panicum is a large genus of about 450 species of grasses native throughout the tropical regions of the world, with a few species extending into the northern temperate zone...
maximum leaves. The interior is made from fibers of C. abietifolia, dry leaves and other plant matter
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
. Females lay 2 to 3 white colored eggs with red-brown spots. The chick's diet consists of insects – parents have been observed offering lepidoptera
Lepidoptera
Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...
n and orthoptera
Orthoptera
Orthoptera is an order of insects with paurometabolous or incomplete metamorphosis, including the grasshoppers, crickets and locusts.Many insects in this order produce sound by rubbing their wings against each other or their legs, the wings or legs containing rows of corrugated bumps...
n adults and lepidoptera
Lepidoptera
Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...
n larvae to hatchlings.
Threats and conservation efforts
The survival of the Elfin-woods Warbler faces two main threats, predation and the destruction or alteration of suitable habitat. Confirmed native predators are the Pearly-eyed ThrasherPearly-eyed Thrasher
The Pearly-eyed Thrasher is a bird found in Puerto Rico and the Virgin Islands, the Bahamas and Antilles. Its genus, Margarops, is considered monotypic today; formerly the Scaly-breasted Thrasher was placed here too...
(Margarops fuscatus), the Puerto Rican Sharp-shinned Hawk
Puerto Rican Sharp-shinned Hawk
The Puerto Rican Sharp-shinned Hawk, , Falcon de Sierra or Gavilán pecho rufo in Spanish, is an endemic subspecies of the North American Sharp-shinned Hawk, occurring only in Puerto Rico...
(Accipiter striatus venator) and the extirpated
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...
White-necked Crow
White-necked Crow
The White-necked Crow is the largest of the four Caribbean crow species. Two other species, the Cuban Crow and the Jamaican Crow , appear to be very closely related to it sharing several key morphological features...
(Corvus leucognaphalus) while unconfirmed native predators include two endemic snake
Snake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
s and several carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
s (from fossil records
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
). Introduced species, such as cat
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
s (Felis domesticus), dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
s (Canis lupus familiaris), Black Rat
Black Rat
The black rat is a common long-tailed rodent of the genus Rattus in the subfamily Murinae . The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world.-Taxonomy:The black rat was...
s (Rattus rattus) and Small Asian Mongooses (Herpestes javanicus) are also potential nest predators. These species have proliferated due to the presence of human-developed facilities, mainly for communication
Communication
Communication is the activity of conveying meaningful information. Communication requires a sender, a message, and an intended recipient, although the receiver need not be present or aware of the sender's intent to communicate at the time of communication; thus communication can occur across vast...
purposes, in the Maricao State Forest and El Yunque National Forest. Two factors contribute to the destruction of the Elfin-woods Warbler's habitat, human
Human
Humans are the only living species in the Homo genus...
s and nature
Nature
Nature, in the broadest sense, is equivalent to the natural world, physical world, or material world. "Nature" refers to the phenomena of the physical world, and also to life in general...
. Human-related habitat destruction includes the construction of communication towers, acquisition of timber
Timber
Timber may refer to:* Timber, a term common in the United Kingdom and Australia for wood materials * Timber, Oregon, an unincorporated community in the U.S...
, and expansion of roads and trails. Nature's contribution comes from natural disaster
Natural disaster
A natural disaster is the effect of a natural hazard . It leads to financial, environmental or human losses...
s such as forest fire
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...
s and hurricanes.
The Elfin-woods Warbler was placed on the United States federal candidate list for Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
in 1999 and the announcement was published on the Federal Register of 10/25/1999, Volume 64, No. 205, pages 57535-57547. The USFWS started to considered the need to protect the Elfin-woods Warbler in 1982. In 2005, a group of scientists, scholars, artists and environmentalists petitioned the Bush administration
George W. Bush administration
The presidency of George W. Bush began on January 20, 2001, when he was inaugurated as the 43rd President of the United States of America. The oldest son of former president George H. W. Bush, George W...
to admit 225 species, among these the Elfin-woods Warbler, to the Endangered Species Act. Of these 225 species, more than one third have been on the candidate list for 20 or more years and half for 10 or more years. Recent studies also show that since the creation of the Endangered Species Act in 1973, 114 United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
species have become extinct
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
, many because of lack of habitat protection by the federal government.
The IUCN first evaluated the status of the Elfin-woods Warbler in 1988. At the time it was given a classification of lower Risk/least concern. In 1994, its status was changed to Lower Risk/near threatened and in 2000, its status was changed to vulnerable
Conservation status
The conservation status of a group of organisms indicates whether the group is still extant and how likely the group is to become extinct in the near future...
, where it remains. The justification for maintaining the species' status as vulnerable is that "There are no direct or immediate threats, but the combination of a very small range and population may have important implications for its chances of long-term survival, and this species consequently qualifies as Vulnerable".
See also
- Fauna of Puerto RicoFauna of Puerto RicoThe fauna of Puerto Rico is similar to other island archipelago faunas, with high endemism, and low, skewed taxonomic diversity. Bats are the only extant native terrestrial mammals in Puerto Rico. All other terrestrial mammals in the area were introduced by humans, and include species such as cats,...
- List of endemic fauna of Puerto Rico
- List of Puerto Rican birds
- List of Vieques birds
- El Toro WildernessEl Toro WildernessEl Toro Wilderness is a National Wilderness Preservation System located partly within El Yunque National Forest on the island of Puerto Rico...
Cited references
USFWS, List of all Federal Register Notices for the Elfin-woods Warbler, http://ecos.fws.gov/speciesProfile/profile/displayAllDocuments!fedreg.action;jsessionid=B578C6BB93986004FE40393A2BE5B719?spcode=B07VGeneral references
- Sociedad Ortinológica Puertorriqueña - Reinita de Bosque Enano. Retrieved on June 15, 2006.