19/05/2018
In a bid to preserve its threatened population, the Critically
Endangered Raso Lark has been reintroduced to an island from
which it has been missing for centuries.
Raso Lark's range has been restricted to the small islet of
Raso, Cape Verde, since humans arrived in the archipelago in the 15th century.
Raso is largely a rock desert, with some sandy parts in the west, and the larks
generally favour small vegetated areas along dry stream beds on level plains
with volcanic soil. The tiny size of the island, plus its susceptibility to
periods of drought, places Raso Lark in a precarious position. The species'
population fluctuates greatly in response to climatic conditions; during wetter
weather, when vegetation grows and food becomes plentiful, it can rapidly
increase, with numbers in the low thousands, but drier periods have reduced its
population to just a few hundred mature individuals in the space of a few
years.
Prior to human colonisation, Raso Lark was believed to be more
widespread, frequenting both Branco and São Vicente Islands. Evidence from
subfossil bone deposits reveal that it once also existed on the islands of
Santa Luzia, São Vicente and Santo Antão. There are also one or two recent
records of vagrants from São Nicolau, including one at Ponta do Barril in March
2009.
With this in mind, a new project, Cape Verde conservation
charity Biosfera 1, in association with the Portuguese Society for the Study of
Birds (SPEA) and other organisations, has launched an ambitious reintroduction
programme on Santa Luzia.
Since 15 April, a total of 37 Raso Larks were translocated
from Raso to Santa Luiza, where they have been successfully released. Each
individual lark has been fitted with a small radio tag so that it can be
tracked, allowing researchers to establish which area of the island they favour
and whether the birds stick together and behave naturally.
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