Rare species: Sociable birch (Vanellus gregarius)

Sociable Failure

Birdwatching attracts a large number of followers all over the world, and for example, the British love for ornithology and the trips they take with expensive observation and photography equipment just to see a certain species are well known. This search can be further refined and focused solely on what are known as rare birds or rarities. Rare birds that stray from their typical routes, breeding or wintering places and are left outside their usual range, becoming an ornithological singularity and triggering, sometimes at unimaginable levels, interest in the particular nature of that presence and the desire of rare hunters or “twitchers” to testify, perhaps, to whatever is the first, only or scarce citation of the species for a location.

In Spain, since 1984, this type of sighting has had a regulatory committee within the Spanish Ornithological Society (SEO/BirdLife) which is responsible for collecting, approving and publishing observations in the Spanish territory of the species and subspecies included in the List of Rare Birds of Spain. For a taxon to be considered rare in Spain, it must have been mentioned in an apparently natural state at least once, which implies having reached this territory by its own means or that there are reasonable suspicions that this has occurred.

On March 18, 2020, one of these oddities was observed by our colleague Victoria while she was carrying out birdlife characterization work on agricultural land for one of our projects in the province of Albacete. Specifically, an adult specimen of Sociable breakdown (Vanellus gregarius) (Pallas, 1771), a bird belonging to the Order Charadriiformes similar in behavior and structure to our well-known European birch (Vanellus vanellus) (Linnaeus, 1758).

Sociable birch, however, lacks the characteristic butt of European birch, which makes it possible to differentiate it from this one quite easily. Somewhat smaller in size and with longer black legs, the sociable birdbird has a striking white eyebrow in summer plumage framed between the black pileus and the eye list, a pinkish gray chest and a black belly; while in flight it has a striking tricolor design (black, white and gray) on the wings and white tail, with a black caudal stripe. During the breeding season, it mainly occupies steppes of Stipa and Artemisia, while migrating and wintering it settles in short grass pastures, dry meadows, plowed fields or fallow fields, etc.

This migratory species breeds in northern and central Kazakhstan and south-central Russia, dispersing to key wintering sites such as Sudan, Pakistan and northwestern India and regularly but in small numbers in Saudi Arabia, Oman and the United Arab Emirates. On the other hand, wandering individuals have been recorded in almost all of Europe, the Canary Islands and Morocco, almost always associated with bands of European birch with which they move (as also happened in our observation) possibly from the same breeding areas.

Avería in Spain

In Spain, the first record of this species is curious, dating back to the 19th century and is a specimen for sale in a market in Cádiz. In 2006, there are already 21 quotes from Avería Sociable in the book Rare birds from Spain and thanks to the information provided by the SEO/BirdLife Rarities Committee for this text, we know that by 2017 there were already a total of 67 registrations. These citations are well distributed across the Spanish orography: Andalusia, Aragon, Asturias, Castile and León, Catalonia, Extremadura, the Valencian Community, the Canary Islands, the Balearic Islands and Castilla La Mancha. In the latter, there have been 3 records, specifically one in the province of Toledo and two in Ciudad Real, to which we must add a fourth, the quote presented in this entry, the first of sociable health for the province of Albacete.

The observation of this species, leaving aside the passions it arouses, is of great importance since it is a bird considered by the International Union for Conservation of Nature (IUCN) to be “critically endangered” (CR). The reason is that its population (of only 2500 - 10,000 individuals) has undergone a very rapid reduction in the last century, for reasons that, although to be determined, according to recent demographic studies, could be due to a low survival of adults, largely caused by the pressure they suffer from hunting along their migratory routes and in wintering areas. In addition, the apparent increase in arrivals and the annual regularity of visits to certain parts of our territory make it difficult to think that it is still due only to lost or wandering individuals.

As we can see, the observation of rare species goes beyond a mere anecdote. The disclosure of these data with a committee of experts, their approval and subsequent analysis of them has great scientific value for the conservation of these species, providing very useful information that can shed light on issues such as changes in their migratory routes, strategies for colonizing new territories or even the response of these species to the pressures exerted by climate change.