Wednesday, 11 January 2017

Spain 11: Sandgrouse

Black-Bellied Sandgrouse
One of the odder groups of birds to be found across Eurasia and Africa are the dry country birds known as sandgrouse. Despite their name they have no relationship to gamebirds, but are much more closely related to pigeons, and in fact they do look very pigeon-like in flight. Another related group are the Mesites, also terrestrial birds but endemic to Madagascar.

Subdesert Mesite
Two species of sandgrouse can be seen regularly in Spain, and we managed to see both of them. The Pin-tailed Sandgrouse Pterocles alchata is the more extreme habitat specialist, using stony and sandy plains with effectively no vegetation cover aside from annual flowers springing up after the rains. The other species, the Black-bellied Sandgrouse Syrrahptes orientalis uses habitats with slightly more permanent ground cover, although still with areas of bare ground. All but one of the sandgrouse we found were Black-bellied.

Sandgrouse are basically seed eaters and although they eat a variety of seeds they show a preference for those of leguminous plants, I presume because they have a higher protein content than those of grasses. When their range includes grain fields they will also feed on those. Where different species overlap they forage in different ways which maximises efficiency.
Pin-Tailed Sandgrouse
The main problem for all dry country birds is obtaining water. Some food can be obtained from the diet, especially in insectivorous species, but seed eaters need to drink and sandgrouse will travel long distances in search of waterholes where they congregate in large flocks. Of course, the chicks cannot fly to the water so instead the parents bring water to them by soaking specially modified breast feathers and then flying back to the nest so that the young can suck water from them.

As with other ground-nesting birds, sandgrouse lay camouflaged eggs – usually 2 03 in a clutch. The young are precocial and leave the nest shortly after hatching. The parents guard the young and provide them with vital shade during the day as well as warmth at night.

Although Black-Bellied and Pin-Tailed Sandgrouse are both listed as Least Concern they are declining in Europe. This is a result of loss of habitat following changes in agricultural practice. Black-bellied in particular seems to be declining in Spain at as much as 79% in 18 years.

(Images from Wikipedia)

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