The Raso Lark (Alauda razae) is a small passerine bird with a highly restricted range, being found only on Raso islet in the Cape Verde Islands. This critically endangered member of the Alaudidae lives in highly arid terrain, and is considered one of the least known birds in the western Palaearctic region, due to its remoteness and the lack of much ornithological study on the archipelago as a whole.
The Raso Lark is restricted to one small island in the Cape Verde group, although historically it is believed to have ranged over two other islands, Branco and Sao Vicente Island; all three of these islands were joined in the last Ice Age. Branco island itself has no permanent water and has never been inhabited by people, a fact that has probably saved the lark from extinction until now.
The Raso Lark feeds by digging in the ground for insect larvae, and bulbs of the nutsedge. Both sexes also feed on grass seeds, and insects such as butterflies, moths and grasshoppers. The female lays one to three eggs after the rains. Courtship behaviour is like that of the Skylark. The incubation time is thought to be 15 days.
The tiny population size, last thought to be ~150 birds, coupled with the highly skewed sex ratio (around 2 males to each female) make this species one of real concern. The reproductive success of the birds is very low, probably due to predation by the near-endemic Cape Verde giant gecko. The Neglected Kestrel Falco (tinnunculus) neglectus is a predator of Razo larks. Although the island is currently free of mammalian predators such as rats or feral cats, and is a closed reserve, the likelihood of a single unauthorized visit causing massive damage remains high. It has been suggested that establishing a second population on the gecko-free island of Santa Luzia, which historically might also have had the lark, should be a conservation priority.
Raso lark eggs
Raso lark chicks
Raso Island with location of Raso lark nest in centre of view
View from Raso