Wednesday, 4 January 2017

Spain 9: Stone Curlew

Eurasian Stone-Curlew B.oedicnemus insularum
The largest of the world’s waders are found among the various species of Stone-curlews or Thick-knees of the family Burhinidae. These strange birds can be found worldwide, often well away from water in grassy or sandy areas, with the notable exception of most of North America. In Europe and western Asia the Eurasian Stone-Curlew Burhinus oedicnemus is the native species.

The nominate subspecies B.o.oedicnemus reaches as far north as southern England, where there are around 300 pairs. In the northern parts of the range they are migratory, wintering in Africa, but in Spain where we saw them on this trip they are resident. In Spain we found a small flock in an abandoned industrial area.

Stone-curlews get their name from their calls which resemble those of the true Curlew, combined with their preferred habitat. They are almost entirely nocturnal and during the day they only usually fly if disturbed. After dark they become much more active and their large eyes give them good vision for the nocturnal insects (plus a few small mammals and reptiles) which are their main prey. Seen by daylight they frankly give the impression of being hung over after a night on the tiles.

Breeding in Stone-curlews starts as soon as they return from their wintering grounds in the spring. The usual clutch is 2-3 eggs and incubation is around 27 days. As with other waders the young leave the nest very shortly after hatching and fledge at a few months old. The birds may make several nesting attempts during the season and may raise two broods. Lifespan is unclear, but the related Bush Thick-knee B. grallarius is recorded as living to 30 years old.
Bush Thickneee in camouflage pose
On the whole Eurasian Stone-curlews are listed as Least Concern by the IUCN. One of the two subspecies found on the Canary Islands, the Western Canary Island Stone-curlew B.oedicnemus distinctus is at grave risk as a result of loss of habitat to tourist development and is probably under 200 pairs or less. The Eastern Canary Island form B.o.insularum is doing rather better and can usually be found on Fuerteventura where I obtained good views a few years ago - the image at the head of this post is a photo I took then. In the UK special conservation efforts have resulted in an increase in the breeding population, but there are still only a few places in the south of England where you can be reasonably confident of locating them.
Great Thick-Knee
In captivity there are several species from around the world that may be seen in various exhibits. In Europe the Bush Thick-Knee from Australia, Spotted Thick-Knee from South Africa, and the European Stone-Curlew are the species most likely to be seen. Unfortunately there are no captive populations as far as I am aware of the two Near Threatened species of Esacus, the Beach and Great Thick-Knees, which are more similar to other waders in that they prefer shoreline and beach habitats rather than dry land

(images from Wikipedia, my own)

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