Great black cormorant
Birds are the most abundant group of vertebrate wildlife in all the natural environments in Spain. Rivers, far from being the exception to this rule, are home to many bird species: some go there to eat, or to nest or to rest, others follow the course of a river, using it as a migratory route to travel between Europe and Africa.
Birds are clearly present during the wintertime. Leafless trees reveal these inhabitants, who are also more abundant and, generally, larger than those that are usually found in fairer weather. However they are not so easy to see in spring and summer, but they can be heard singing among the leaves that protect them. Identifying these birds by their song is a complex task for all but the experts.
The great black cormorant, which breeds and spends summer in North-eastern Europe, is a migratory bird that is common in Mediterranean countries, where the climate is more temperate.
Great black cormorant
The night heron makes its nests in the riparian forests of Southern Europe and Asia, however it migrates to Africa and Southern Asia during the winter.
Little ringed plover
The kingfisher enjoys temperatures and conditions here that are ideal for year-round habitation, especially in rivers and other areas where there are bodies of water.
Western cattle egret
The warming of the planet over recent decades is causing significant changes in the structure and functioning of natural systems, as well as in the way they work. In the context of the Mediterranean region, it is difficult to identify those changes related to climate change that may have occurred in the rivers of the region, as they are already highly regulated and have been altered by excessive catchment areas and a wide range of infrastructures. Recent studies however indicate that low river flows and the frequency of extreme events are increasing, from droughts through to floods. With respect to birds, mating calls and reproductive activity are now being detected one or two weeks' before they were previously, while migrations are also beginning and ending both earlier and later. This often leads to timing issues when it comes to the availability of food sources, whether plant (fruit) or animal origin (the emergence of aquatic insects, the activity of amphibians, rodents and other bird species, etc.).
Illustrations: © Toni Llobet and Martí Franch
Recordings and audio: © Eloïsa Matheu