More parrots and fewer sparrows in Catalonia

BarcelonaThe noise of parrots is no longer strange or exotic-sounding in the most populated areas of Catalonia, although 40 years ago they were an anecdote in the midst of the usual sparrows or serins. The list of newly arrived birds in the last decades is quite long –there are 17– and exotic birds have had a lot to do with it because they make up to half of the novelties detected by the third Atlas of nesting birds in Catalonia, a project led by the Institut Català d'Ornitologia (ICO), which is the most comprehensive study ever made of the birds that inhabit Catalonia. In view of the overall numbers, things have not gone badly for birds: it is estimated that between 8 and 12 million pairs of birds breed each year and the 233 species that can be found in some corner of the country are a very broad representation (39%) of Europe's bird wildlife.

When compared to four decades ago – when the atlas was made for the first time – the results are clearly positive. However, when compared to only 20 years ago, things are not so chirpy. "In the first decades of this century we can already detect symptoms that things are not going so well and that things are stagnating," warns the general director of the atlas, Sergi Herrando, who is a researcher at ICO, CREAF and the European Bird Census Council (EBCC). Some native species that are still clearly predominant, such as the house sparrow or the European serin, are in clear regression, a fact that "gives clues about the extent to which natural systems are pressured by the entire human presence," says the expert, who adds that more than a hundred of the species that inhabit Catalonia have a population that is already considered "scarce" because it does not reach 2,000 breeding pairs. "There has been no clear extinction, but we have some hanging on by the skin of their teeth, they are in extreme danger and will probably become extinct," Herrando predicts.

The third edition of the atlas allows to see trends and birds offer "a very clear x-ray" of what has happened in the country's landscape over the past 40 years. The abandonment of the rural areas and the expansion of forests has been both an attraction for certain species – including some from other parts of Europe – but also a hindrance for those that lived on the margins of agricultural land, increasingly difficult to find. Wooded areas have been ideal for the robin, the chaffinch or the golden oriole, others such as the turtle dove have been suffering from being cornered, especially in mountain areas where decades ago there were fields or pastures. In addition, the increasingly intensive agriculture in the plains, with large monocultures, the use of pesticides and the elimination of the margins between fields is also condemning to the decline of the shrike or the little bustard.

Among the endangered species, the case of the shrike stands out, a bird that now is bred in captivity and which is only just surviving. "There have been years in which no chicks hatched and here is the only place on the peninsula where they still exist," Herrando explains. This bird is typical of extensive agricultural environments.

The effects of climate change

The analysis by areas has unearthed interesting facts: the Cerdanya is the region with the most birds, and the northern half of the country generally has more birds than in the southern half. What has not been detected, for the moment, is any generalised displacement of species towards the north in search of cooler temperatures, which could be attributed to the planetary warming that is already beginning to affect the weather. But although it is not widespread, some species are moving northwards. It has been detected that the stonechat is disappearing from Mediterranean areas and is concentrating in the Pyrenees and the cuckoo has moved to higher altitudes, Herrando says.

In the Delta de l'Ebre, one of the most vulnerable areas to the climate crisis, some species also face clear threats. Whereas 20 years ago most of the world population of Audouin's gull was concentrated in this area, now very few specimens can be found and the rest are scattered around other parts of Catalonia. This is due to the delta's loss of surface area of the delta – an effect of climate crisis and also the lack of incoming sediments – as well as new land predators, the expert stresses. There is also the case of the egret, typical of wetlands, which has suffered a decline since 2006 due to action being taken to stop apple snails.

The information compiled by the atlas, the result of four years of work by 1,200 ornithologists on the grounds, is only "a door to investigate," according to Herrando. The level of knowledge it allows us to reach, he insists, does not exist in any other biological group: "With this starting point, I am confident that the puzzle of biodiversity can be built, identify what we have, how it is changing and how to conserve it. "The book helps us to better understand the environmental pressures that affect our birds and, by extension, our ecosystems, and to be able to correct them as a public administration," adds the director of Environmental Policies and Natural Environment of the Generalitat, Antoni Ferran. For example, one of the surprises of the work has been to discover a "hot spot" of biodiversity in Cerdanya, as also happens in other valley areas.

The Government intends to replicate the method and, from next year, to launch the first atlas of mammals in Catalonia, a project that also wants to have public participation of all naturalists to be as comprehensive as the bird atlas is.