Saturday, 31 December 2016

Spain 8: Bustards

Breeding plumage male Little Bustard in the open - NB:This never happens
There are three species of Bustard that breed in Europe and I am glad to be able to say I have seen all three. Admittedly the Houbara Bustard only counts if you include the Canary Islands in Europe, when in terms of their location and endemic species they are more accurately part of North Africa, but they belong to Spain so I am going with it. This year I have had good views of the mainland species, Little and Great Bustard, in Portugal this spring and again in autumn in Spain.

As a group, the vast majority of bustards are African. Outside Africa a given region usually only has one or two species in the same area, and telling them apart is straightforward. They are all birds of treeless areas, either grassland, savannah with some bushes, or desert, and they all as far as is known have similar diets of plant materials, insects, and for the larger species reptiles and small mammals. They nest on the ground and adult males are almost invariably larger than females, and have spectacular courtship displays, often in leks.
Little bustard female - visible in autumn fields
Seeing Little Bustard Tetrax tetrax during the breeding season is usually rather difficult. At that time they are spending most of their time concealed in grass as high as their heads. Males display in a dispersed lek by leaping up into the air to display their black and white necks while uttering the distinctive call that gives them their French name of Outarde canepetiere – roughly translated the farting bustard. I saw them this spring in Portugal on their breeding grounds on the edge of the great Iberian steppe. By November they have finished breeding and congregate in large flocks on cleared fields, and we found a flock of at least 150 birds.

As with many birds that are dependent on low intensity grazing and traditional farming methods, Little Bustards have been heavily affected by changes in farming practise, and the population in western Europe is declining. In Spain they are resident, but further north they are migrants, wintering in Spain and North Africa. In France there is a reintroduction project aiming to boost the population with captive bred birds. To the east there is another population which ranges from the Balkans east through Turkey, Russia and Kazakhstan which at least at present seems to be doing rather better, but overall the IUCN lists the species as Near Threatened.
Male Great Bustard
The other bustard species we found are one of the characteristic species of Eurasian steppe habitats, the Great Bustard Otis tarda. I have seen these several times before, but they are always an amazing sight, especially the gigantic males, which at over 1m tall and a weight of 18kg are among the heaviest of flying birds. As with Little Bustards, the population is declining as a result of changes in agricultural practise, and as a result of the birds’ giant size they need large areas of suitable habitat when breeding. An interesting feature of the species is that although they are omnivorous, the males especially show a deliberate preference for poisonous blister beetles during the breeding season. The beetles contain cantharidin, a highly toxic compound which has medicinal properties. However, it has also been used (in very small quantities) as an aphrodisiac by humans, and it has been suggested that that may be part of the reasons the bustards use it as well. I expect debate on this may go on for some time.

Although matters may have stabilized in Spain the eastern population is declining rapidly and consequently it is currently listed as Vulnerable by the IUCN. There have been some attempts at reintroductions, notably to Salisbury Plain in the UK, but although there have been a few chicks raised at present it looks rather unlikely that a viable population will be established.

(Images from Wikipedia)

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