TThree Osprey chicks were born in an artificial nest installed in one of the high voltage electricity towers belonging to Red Eléctrica de España located near El Rocinejo reservoir, in the province of Cadiz. With these chicks, which are in perfect condition and have been ringed by technical personnel of the Environment Ministry, the stable Osprey population in Andalusia now exceeds 20 specimens.

The Osprey was absent from the Andalusian region for over three decades until last year, when the first offspring were born as a direct result of a reintroduction programme of birds of prey into the areas of Huelva and Cadiz.

Nest building has been driven by the persistent customs of the male, reintroduced in Andalusia in 2008, to use the electricity towers as perches during their migratory stay, which led experts to believe that this could be an excellent place for the establishment of a breeding pair.

Red Eléctrica de España received the proposal and evaluated the scope of the project to reach an agreement with the Environment Ministry of Andalusia to undertake the challenge and facilitate the construction of a platform that could accommodate a nest where a pair of Osprey could settle-in and breed. The nest was built in the winter of 2010, the male Osprey did not take long to mate and two years later we saw the birth of the first chick in this unique facility, a happy event that was repeated again this spring, with a brood of three new young.

Background
The reintroduction programme in Andalusia of the Osprey is a pioneering initiative of the Ministry of Agriculture, Fisheries and Environment of the Junta de Andalucia (Government of Andalusia), which commissioned the scientific leadership of Miguel Ferrer, a research professor of the Doñana Biological Station (CSIC) and president of the Fundación Migres. It began in 2003 with the release of four six week-old chicks, relocated from Finland, which were housed in an artificial nest built on the banks of the reservoir of the river Barbate (Cadiz).

After that first experience, there was an average annual increase of 20 chick specimens relocated. In total, to date, 164 chicks of the species have been reintroduced: 86 in the southern province of Cadiz and 78 in the Paraje Natural de las Marismas del Odiel (Huelva). The aim is to re-establish a viable breeding population of Ospreys in continental Spain, where they have not bred since the 1980s.

To achieve this, it was decided to resort to the technique of hacking or semi-rural farming, which involves removing chicks from their original nests and moving them to other artificial nests, where they remain until they are able to fly by themselves. Thus, the young birds identify the reintroduction area as their home area, and it is where they will return to breed when they reach sexual maturity.

Success of the project
To date, the results of the project are very positive. The first milestone achieved was the establishment, in 2005 and 2006, of a breeding pair in the Guadalcacín reservoir, about twenty kilometres from the point where they were initially released in the south of Cadiz. The second milestone was the successful return to the release areas of the first Ospreys reintroduced, after a stay of two years in the African wintering grounds.

In April 2009, there was a third and final event: in el Paraje Natural Marismas del Odiel, the first eggs from a pair from the project hatched: and three chicks were born. In 2010, the same pair gave birth to a new chick and in 2011, two more chicks. In 2012, six breeding pairs made different territories of the provinces of Cadiz and Huelva their rearing sites, and have given birth to a total of 10 chicks, confirming the success of the project.

This series of successes is due, amongst other things, to management effort and work involved in the release of these birds and that have led to the optimum conditions for breeding of specimens that return, as has been the case of the installation of a nest on an electricity tower of Red Eléctrica de España, the construction of special towers and perches, population monitoring, surveillance to avoid dangers and injury, the ringing of the species, etc.