IX EUROPEAN CRANE CONFERENCE – ARJUZANX
3 – 8 December 2018 Sabres,
Aquitania, FRANCE
Census-counting of Common cranes in El Oso (Castile and Léon, Spain)
We are very happy to participatee in this IX European Crane Conference, which this year takes place in the beautiful Landes in the New Aquitaine region.
As you all know, the Common crane represents a heritage belonging to the community of citizens of Europe as well as of other continents, and it is a heritage that we strive to observ, study, conserv, and protect. To the conference last year, in Gallocanta in Spain, we owe our knowledge of this species’ s situation in Europe.
We would like to start by telling you something about the geographical situation of the steppe lagoons of El Oso in the Avila province.
The Avila province is part of the largest region in Spain (93.813 km²) and in the Iberian Peninsula, made up of Spain and our neighbour Portugal.
El Oso is located in the north-western quadrant of the Peninsula, and shows the following bioclimatic features:
Its geographical coordinates are 40.51’16.44’’N and 4.45’52.20¨¨W, with an altitude of 884 meters above sea level. UTM coordinates (ETRS89) X351281 Y4524111.
The climate is continentalized Mediterranean, with a Lang ariditiy index of 32,05, and characterized by long arid periods and an average annual rainfall of about 411 mm.
The average temperature is not very high: 12,4º C. The coldest month is January, with an average minimum of -2,1º C, and a measured absolute minimum of -10,1ºC. The hottest month is July, with an average maximum of 32,1º C, although it is possible to measure absolute maximum temperatures of up to 37,4º C. It is worth stressing that recorded thermal variations of absolute maximums may reach almost 40º C in the area.
El Ose is located in the geographical area of La Moraña, between the rivers Adaja and Arevalillo, which through the different geological eras (mainly the Tertiary and Quaternary) have shaped a series of deposits and soil horizons. Due to its closeness to the Mountains of Avila, there are deposits of loams, clay, sand, and a rich and -until recently- well-preserved aquifer, named Los Arenales, which surfaced spontaneously at different spots of the penillanura. The inclination from north to west is about 0,5-1%. These surfacing waters have given rise to a number of wetlands that have formed a landscape of which some parts still remain in spite of the alteration caused by agriculture.
In El Oso we can find all these remnants that we wish to conserv: the land from the Tertiary and Quaternary with its different botanical elements and current crops, the wetlands with its broad range of wildlife species, and its inhabitants in their continuous evolution.
79% percent of the municipality’s territory is covered by cropland, 7,7% by pinewoods, 6,4% by grassland, 6,3% by salt marshes, and 0,6% by the lagoon. The main crops are barley, wheat, rye and, to a lesser extent, pulses.
This wetland area, known as “the Lagoon of El Hoyo”, is one of the main stops for numerous bird species in the area, both in their prebreeding and postbreeding migration. Currently, part of the wetland is included in the Regional Catalogue of Wetland Areas of Special Interest, declared and registered by the Regional Government (Junta) of Castile and León, which has the full competence for the management of the natural resources in the region. The area covered by standing water may vary from one year to another, but amounts on average to about 30 hectares (about 75 acres). Since the year 2001, 15,88 hectares have been a protected area. However, in spite of its importance, this wetland area is not included in the Natura 2000 network, although it was included by SEO Birdlife as IBA No. 425 at the start of the administrative record. For several years its inclusion in the Natura 2000 network has been annualy requested, so far unsuccessfully.
On a national level, the first census-counting was carried out in 1960, when professor Bernis started to collect data about cranes. In El Oso, older people in the village acknowledge having seen cranes, and heard their caracteristic trumpeting sound, since they were little, although the official count did not start until the 70s. In 1977 this wintering population of cranes was discovered; at that moment it was the most northern population known. These data were included in the first national census of 1979-80 (Fernández Cruz et al., 1981), and later in the edition of 1987-88 (Alonso et al., 1990) In 1979 the maximum number of birds recorded were 243. Thus, the collection of data regarding the phenology and spatial ocupation, as well as the roosts and haunts of the cranes, has been going on for over 40 years in El Oso.
We are thankful to all the volunteers who have contributed to this data collection, which often takes place on the shortest and coldest winter days.
The graph shows a more or less stable number of cranes that land on this site on their migration route towards their home ranges and wintering areas, found more to the south-east. However, there is some fluctuation due to the changes in the weather and the harsh conditions, like coldwaves and snowfall, that are common in the continental territories of Europe, which make the cranes travel longer distances in search of feeding grounds.
We would like to highlight the increased presence of this species in the area in the last years, as a consecuence of the expansion of irrigated cropland, mainly cornfields which stubble fields and left-overs the cranes use for feeding grounds.
Since 2010 we have been collaborating with the iCORA platform.
We are thankful to all the people who have been contributing to make this small site known, in order to protect it as a heritage for future generations: Carlos Bermejo, mariano Hernández, Luis José Martín, Ignacio Martín, José María González, David Sánchez, Victor Coello, Pepe Rodríguez, Jorge Leonor, María Cruz, Juan Ramón Cuervo, Santiago Delgado and others.
Recordings of ringed cranes in El Oso and municipalities nearby
Since 2010, 26 birds have been identified and their corresponding ring combinations sent to iCORA. Most of these cranes had originally been marked in Germany. There have also been two from Estonia, one from Norway, and one from the Czech Republic.
The following chart shows (starting at the top) the data that are recorded and sent: the ring code on the left tibia, the ring code on the right tibia ; the country where the bird was ringed, the year, the person in charge, and the cronology of the observations in the area.
The 1992 Seville Universal Exposition marks a milestone in the study and monitoring of big migratory birds like the ones that land in the lagoon of El Oso.
In collaboration with the German Pavilion, the Doñana Foundation started to raise funds for the restoration of the wetlands in Doñana National Park. Hans-Gerd Neglein, the German exhibition curator and Director of WWF Germany, played an important part in this context. In 1994, on the suggestion of Beltrán Ceballos (Doñana Foundation), the routes of the migrating birds on their way to Doñana also became an object of study and restoration. At the end of this year, WWF Germany, WWF Spain and ADENA decided to include the two lagoons in San Juan de la Encillina and El Oso in their project.
Some years later, at the beginning of this century, a collaboration agreement with SEO BirdLife was signed, a small artificial pond was created near a new observatory, native trees and shrubs were planted nearby, and work was made on the observatory by the road to Hernansancho.
Although the original idea was to follow the route of the Greylag goose, today the Common crane is the highlight of the site.
Environmental commitment of El Oso
The municipality of El Oso is pursuing a sustainable development, based on its natural resources: the lagoon, the Adaja riverside, the cropfields, its rich wildlife with populations of Lesser kestrel, Great bustard, Iberian imperial eagle, Common crane, and a large number of steppe birds.
In recent years the Town Council have carried out many actions and activities. For example:
- The construction of “Laguna de La Moraña Centre”, which the Council hopes will be a source of employment for all the area of La Moraña. The Centre has been financed by local public money and private donations, as well as by Spanish and European subsidies.
- A Biodiversity Plan is being drawn up, with a comprehensive environmental inventory of the municipality. It is sponsored by the Biodiversity Foundation.
- El Oso is a member of the Municipal Network for the protection of the Iberian Imperial Eagle, under the Ecological Transition Ministry.
- It is also a member of the Municipal Network for Biodiversity, of the Spanish Federation of Municipalities and Provinces.
- It is one of the 20 stations of BIRDFLYWAY created for the observation of migratory birds.
- A new observatory has been built, and about 100 nest boxes for Barn owls and Kernels have been installed in the area, in order to limit the number of voles and other rodents, and thus to avoid the use of poison in agriculture. There are also several artificial nests for White storks, and more than 100 nest boxes for insectivorous birds have been installed in the pinewood and trees in the local area of El Oso. Furthermor, there are hides for photographing passerines, migrants, and birds of prey.
- Every summer an Interational Camp is organized, in which young people from countries in the European Union stay in El Oso for some weeks, working as volunteers in programmes related to the lagoon and taking part in different activities in the village.
- In November a seminar about Environment and Tourism is oganized, where issues such as Birdwatching tourism, Wetlands, Green employment, Nature tourism, or Natural and cultural heritage are discussed.
- In August this year, the Plenary session of El Oso Town Council decided to apply for an inclusion in the Natura 2000 network as a ZEPA or ZEC. The site has already been included as a IBA – an Important Area for Bird Conservation- by SEO/BirdLife, with the following references: IBA No. 425 / El Oso-Corridor of Adaja River / 38.259,33 Ha. / Number of species that meet the IBA criteria according to their global importance (A2), European (B3) or of the European Union (C4).
Finally, the group of environmental studies Galérida Ornitólogos Abulenses GOAgea
and the Town Council of El Oso would like to welcome you to come and enjoy the observation of species -apart from the Grus grus- like Aquila adalberti, Gypaetus barbatus, Aegypius monachus, Elanus caeruleus, Fulica cristata, Otis tarda, Pterocles alchata, Clamator glandarius, Caprimulgus ruficollis, Galerida theklae, Chersophilus duponti, Oenanthe leucura, Phylloscopus ibericus, Cyanopica cooki and Passer hispaniolensis, some of which can be found in the territory of El Oso, and all of them in a 150 km radius.
Text, images, compilation of data: Víctor Andrés Coello Cámara
Translator: Lena Peterson
