With its harsh song and showy plumage, the European roller has for decades been the perfect ally to naturally combat insect and small animal pests that endanger crops. However, in recent years, the breeding pairs of this small migratory bird, which is present from spring in practically the entire Iberian Peninsula, have been increasingly threatened.
The feeding of this bird is what makes it a key part of natural pest control. Their diet is based on insects and small vertebrates such as rats and other rodents. Hence, it is of vital importance to maintain the presence of the European roller, as it allows the reduction of pesticides and phytosanitary products, that make the cultivation process more expensive and are harmful to the environment.
Aquamarine in color with hints of gold, the European roller is a very unique species. In April, they leave Africa in search of a place to raise their young. It expands from that moment fundamentally by the middle basin of the Ebro, Extremadura and the eastern half of Andalusia, but also reaches the west of Castilla y León, Castilla-La Mancha and Murcia.
There it takes advantage of all kinds of holes to build its nests. After breeding in Europe, the roller flies over the Mediterranean on various fronts, rests in sub-Saharan Africa and spends the winter in southern Africa. Every year, the European Roller (Coracias garrulus) travels about ten thousand kilometers to breed and winter in our country. However, that is becoming mission impossible.
Spain has between 2,000 and 6,000 couples, but in recent years this figure has been declining and today there are 40% fewer, according to SEO Birdlife. The main problem for the conservation of this bird is related to the loss of habitat as a result of agricultural intensification, changes in cultivation, the disappearance of wooded boundaries and the progressive deterioration of rural constructions suitable for the installation of the nest.
On the other hand, andhe massive use of insecticides affects the availability of prey and can cause poisoning; accidents on power lines and run overs are also frequent. For all these reasons, and given the negative trend experienced in the populations of this bird, the European Roller has been included in the Red Book of Birds of Spain in the category of ‘Vulnerable’ and is considered ‘Of special interest’ in the National Catalog of Endangered Species.
The measures for its conservation go through the maintenance of traditional agriculture and extensive livestock, control over the use of pesticides and maintenance of the wooded area. Likewise, SEO Birdlife is committed to investigating more about the biology of the bird as well as the problems that are leading to the progressive decline of the species.
Nest boxes are, in this sense, a new resource that is having good results with this species. This program, which began in March 2021, has achieved a 75% occupancy of both European rollers and species. A considerable figure considering that up to now, the occupancy rates of this type of initiatives in other places are around 25% the first year.
The boxes have been installed in irrigated agricultural plots in the municipalities of Almudévar (8), Almunia de San Juan (47), Binaced (2), Candasnos (4), Huerto (8) and Lalueza (10), all of them in Huesca. To guarantee their operation, the nest boxes have been installed in trees, telephone poles and some artificial poles created with the aim of “offer nesting places that allow the presence of these birds so that they can exercise their function of natural pest control”, as explained by the delegate of SEO/BirdLife in Aragón, Luis Tirado.
Given that it is a simple management method that gives good results, the experts insist that it should be a management initiative that is implemented throughout the territory.
Reference articles: https://onlinelibrary.wiley.com/doi/10.1111/ddi.12345https://seo.org/ave/european-rattle/