Conservation of the ash harrier in Campo de Tejada (Huelva)

Biologics

HEY Ash Harrier (Circus pygargus) is a daytime, steppe raptor that arrives in our fields in the first days of March from its winter quarters in the Sahel and Southern Africa. The male has a striking ash color in its livery, hence the name of the species, while the female has darker and more muted tones ideal for blending in crops, which favors their camouflage during the incubation of the eggs.

Once their spring migration is over, the males settle in domain plots and the courting of the females begins, which will end with the first copulation in early April and the construction of the nests. After laying, the incubation will last about 28 days, at the end of which the chicks will begin to hatch in a staggered manner.

Where do you live?

The species selects as its preferred habitat large open areas, agricultural meadows, plains, cereal steppes and, in general, deforested plains, from mid-mountain grasslands and heathland to reeds linked to marshes or wetlands (Sayago, 2011). With regard to the Tejada Field, the population of ashy harriers almost entirely nest on wheat crops, although some nests on barley, greens for livestock grass, irrigated crops or wild vegetation on agricultural borders have been determined on an occasional and very small scale. The substrate offers optimal conditions for nesting, since it provides an abundance of nutrients for the species, as well as cover and protection for the chickens, which would explain the preferred selection of this habitat.

What does it feed on?

As for its diet, the ash harrier is a carnivorous raptor with a wide trophic spectrum, presenting a diet of the type Euryphaga and therefore quite diverse depending, in any case, on the local and temporary supply of the food (SEOƒBirdLife). During the months that the species nests and breeds in our region, the prey captured preferentially by the ash harrier in the Tejada countryside are macroinvertebrates (45%) such as grasshoppers and cicadas (Herrera Maris− cal, 2007), which are complemented by small and medium-sized vertebrates, especially rodents (mice) and insectivores (rural mice), accounting for up to 30% of their diet, also including granivorous birds and birds (20%) as well as lizards and small culls fibers (10%).

In this sense, the wide taxonomic spectrum of insects that consume leaves, stems and other green parts of cultivated plants (grasshoppers, cicadas, etc.), as well as the numerous species of small granivorous birds that feed on crops, make the trophic pressure that the ash harrier exerts on these primary consumers essential for the balance of their populations, thus avoiding significant damage to the economic performance of agricultural production.

Conservation hazards for the ash harrier

As for its problems, of all the peninsular avifauna, the ash harrier is one of the species that has the greatest number of threats. In addition to the risks inherent to the natural dynamics of ecosystems (predation, competition, diseases, adverse weather, etc.), we must also add others of a strictly anthropic nature and which are the real causes of the population decline that the species has been suffering in recent decades. With regard to agricultural practices, and as a factor repeatedly mentioned and common to all ground-nesting birds, mechanized cereal harvesting and subsequent adjacent tasks described above stand out for its negative effect.

In this sense, the action of the harvesters represents the main risk of reproductive failure. The early harvest of the cereal where the nests are located, whose start date varies with the weather, represents the nuclear problem and the greatest threat to the conservation of the species (Cejuela López, 2017).

Harvesters pose the main risk of reproductive failure

On the other hand, the nidiculous and semialtritial nature of ashen harrier chickens further accentuates the chances of being run over or mutilated by harvesting machines. Unlike the chicks of other threatened species (bustard, sison, caravanna, gangue, etc.), which, due to their status as firefighters and precocials, quickly leave their nests, ashy harrier chickens remain on the nest platform for about five weeks, a circumstance that further aggravates the risks of mutilation and running over.

From idea to action

Sensitive to this problem, in the spring of 1997, biology professors Ignacio Herrera and José Antonio Rivera founded environmental volunteering for the rescue of the ash harrier in the Tejada Field, an initiative whose fundamental objective would be to involve citizens in the conservation of this species and guarantee its continuity in the Tejada Field. The volunteers of Ltuci Verde have carried out different tasks since the arrival of the harlots in our fields: locating the breeding colony, marking and marking the nests, building metal fences, census of juveniles, dissemination among the agricultural community and numerous environmental education workshops in schools and institutes to sensitize people in our region to the problem of the species.

Based on the results obtained, it can be inferred that the condition caused by harvesting machines on the breeding colony of the ash harrier in Campo de Tejada, thanks to management measures, has been reduced, on average, by 86%, which highlights the favorable balance of all action measures.

This environmental volunteer project, with more than two decades of existence, has been a fabulous example of solidarity and altruistic commitment. In these times when threats to the planet's health are becoming increasingly visible and undeniable: climate change, loss of biodiversity, widespread pollution, extinction of species, etc., the emergence of a project like this is a priceless gift of optimism and hope. It reflects the knowledge, work and selfless dedication of a select group of fellow citizens for 22 years (I am interested in highlighting the figure of 22 years), all focused on the protection and protection of a bird. A small traditional bird of prey in the area that appears every spring in the fields of Tejada after flying thousands of kilometers from their African territories.

It might seem that the fate of a few dozen birds in an Andalusian region is a smaller story. I am convinced of the opposite, because it is not the most important thing, if it is, the fate of a population of harriers. What is substantive is the will sustained over time to find another way of relating, as a species, to our environment to avoid the generalized impoverishment to which the prevailing economic model wants to lead us. The resulting message is clearly positive; in a generalized context of increasing decline, the population of ashen harriers in Tejada is maintained. Farmers have been sensitive to the requirements of volunteers and a social awareness has been forged about the goodness of the presence of these raptors in our skies.

To further reinforce this comforting sense of optimism, the Andalusian administration has also surrendered to the work well done and the perseverance of a group of young people, some not so much after 22 years, granting them various and well-deserved awards.

Without a doubt, an injection of optimism to face with hope of success the important challenges that call into question the existence of the planet, as we have known it, and its inhabitants, including us.

Author: José María Fernández Ojeda