The Raso Lark, (Alauda razae) is a small passerine bird with a highly restricted range, being found only on the island of Raso 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.
Description
The Raso Lark is restricted to one small island in the Cape Verde group, although historically it is believed to have also ranged over two other islands, Branco Island and Sao Vicente Island ; all three of these islands were joined in the last Ice Age. The island itself has no permanent water and has never been inhabited by people, a fact that has probably saved the lark from extinction until this point.
The Razo Lark feeds by digging in the ground for insect larvae , and, in the case of males, bulbs of the nutsedge. Both sexes also feed on grass seeds, and insects such as butterflies, moths and grasshoppers. The difference in feeding behaviour accounts for a significant difference in bill size, with the males averaging longer. The females lay one to three eggs after the rains. Courtship behaviour is like that of the Skylark. The incubation time is thought to be 15 days.
Threats to the Raso Lark
The tiny population size, last thought to be around 70 birds, coupled with the highly skewed sex ration (around 2 males to each female) make this species one of real concern. The reproductive success of the birds is very low, mostly due to predation by the near-endemic Cape Verde giant gecko . 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 conservation priority.
Reference
Status, ecology, behaviour and conservation of Raso Lark Alauda razae, Bird Conservation International 13, Donald et al, 2003.
External link
