Santa Marta warbler (Basileuterus basilicus)
|Size||Length: 14 cm (2)|
The Santa Marta warbler is classified as Vulnerable (VU) on the IUCN Red List (1).
The Santa Marta warbler (Basileuterus basilicus) is known as the ‘jewel of the forest’. This remarkable bird has a small, delicate body, with striking yellow and olive-green plumage and intricate white streaks across its dark blue head. A sharp, slender bill is characteristic of this species, and its orange legs are slightly thicker than a toothpick (3). Both the male and female Santa Marta warbler are brightly coloured throughout the year (4).
Known for its beauty and speed, this elusive songbird is incredibly fast, fluttering constantly from bush to bush. As such, it is rarely observed for long periods of time (3) (5). Like all species of the genus Basileuterus, the Santa Marta warbler emits loud, high pitched symphonies and trills (2) (6).
The Santa Marta warbler is endemic to Colombia where it is found to the north, in the Sierra Nevada de Santa Marta. However, its distribution is fragmented, and its abundance varies from common to rare across its range (1) (2).
The Santa Marta warbler inhabits humid montane forest or woodland. It mostly moves on the ground and is often found in the underbrush or in dense thickets. The Santa Marta warbler tends to dwell near small mountain streams or ravines, and it also frequents areas with dense Chusquea bamboo cover (2) (3) (4).
The Santa Marta warbler feeds mainly on small invertebrates (6), although it also consumes berries, seeds, nectar and the juice of various fruits. The sharp, slender bill enables the Santa Marta warbler to extract insects from minute cracks in tree bark and the gaps between blades of grass. Species of the Basileuterus genus are known to rapidly flap their wings and tail to flush insects out from their hiding places. Foraging takes place mostly on the ground and a diet mainly comprising of insects means that the Santa Marta warbler faces some competition with lizards over food sources (3) (4) (5).
Although little specific information is known about the Santa Marta warbler’s breeding habits, tropical warblers of the New World are all believed to have similar reproductive cycles. Juveniles moult into colourful adult plumage in the late summer and pairs are formed at an early age. Interestingly, the male and female remain pair-bonded throughout the year (4) (6).
This species first breeds at around a year old and breeding occurs during the rainy season, when there are more insects on which to feed the young (4). The female spends a week building a domed, covered nest, which is concealed behind foliage to prevent nest predation (4) (6). A small, single clutch is produced, containing two to four eggs. Incubation typically lasts 16 to 17 days, and the young remain in the nest for a further 12 to 15 days after hatching.
Species of the Basileuterus genus have complex social systems. Juveniles remain with the adult birds throughout the year, helping to protect the nest and watch for predators, and may subsequently inherit the territory. Territories are permanent and must be protected year round, and both the male and female aggressively defend the territory against intruders of the same species (4).
The main threat faced by the Santa Marta warbler is habitat loss. Estimates suggest that 21 percent of its original forest habitat has been destroyed by the development of cattle ranches and plantations. The north slope of the Sierra Nevada de Santa Marta, where the majority of the population of this species is found, is already extremely degraded. It is thought that up to 85 percent of the Sierra has been affected to some extent by illegal agricultural expansion, logging and burning (1) (2).
Habitat fragmentation has also pushed the Santa Marta warbler to the edges of its range, where it faces increased pressure from brood parasites, and racoons and possums that feed upon its eggs (6).
Some populations of the Santa Marta warbler occur within the protected Sierra Nevada de Santa Marta national park; however, further research is required to assess the state of the population and its ecological needs. In the long term, a management and conservation strategy is required for the Sierra Nevada de Santa Marta, to preserve the montane forest habitat this species requires and prevent further population declines (1) (2).
Find out more about the Santa Marta warbler and its conservation:
BirdLife International - Santa Marta warbler:
Neotropical Birds Online - Santa Marta warbler:
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- Brood parasite: an animal that lays its eggs in the nests of members of its own or other species; the host then raises the young as its own.
- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Genus: a category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
- Incubation: the act of incubating eggs, that is, keeping them warm so that development is possible.
- Invertebrates: animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.
- Montane forest: forest occurring in the montane zone, a zone of cool upland slopes below the tree line.
- Moult: periodic shedding of (usually) the outermost body covering (such as feathers, fur or skin) during growth and development, or at specific times of the year.
- Territory: an area occupied and defended by an animal, a pair of animals or a group.
IUCN Red List (July, 2011)
BirdLife International (July, 2010)
- Hutchins, M., Jackson, J.A., Bock, W.J. and Olendorf, D. (2002) Grzimek’s Animal Life Encyclopaedia. Gale Group, Michigan.
- Morse, D.H. (1989) American Warblers: An Ecological and Behavioural Perspective. Harvard University Press, Cambridge, Massachusetts.
- Thomson, A.L. (1964) A New Dictionary of Birds. Nelson, London.
- Elphick, C., Dunning Jr, J.B. and Sibley, D. (2001) The Sibley Guide to Bird Life and Behaviour. Christopher Helm, London.