Conservation of the Roseate Tern in Brittany

PROJECT DESCRIPTION

BACKGROUND

The roseate tern (Sterna dougallii) is very cosmopolitan, but its global range is highly fragmented. Most of the global population, about 50 000 pairs, breeds outside Europe. In the North Atlantic region, the roseate tern breeds on the north eastern coast of America and in Europe mainly on the Azores, in the Irish Sea region and on the north coast of Brittany in France.

In recent years, the number of individuals worldwide has remained the same. In Europe, it has increased steadily everywhere except in France. On the north eastern coasts of America populations have declined recently for reasons not fully understood. In France, Roseate tern’s populations fell during the 1980s from an average of 360 breeding pairs in 1954-73 to 90-100 pairs after 1980. Since then, the numbers have continued to decline.

The colony of Brittany supports nearly 100% of the French population and approximately 5% of the European numbers. The main threats are uncontrolled human disturbance, predation by American mink (Mustela vison), predation and spatial interspecific competition with gulls (Larus ssp), and unfavourable habitat management of potential nesting sites. The French population is also threatened because for the last 15 years there has been only one nesting site. As a result, it is extremely vulnerable to accidental events. Today, the Île aux Dames in the bay of Morlaix holds the near-total French population of Roseate – 70 pairs. The project site includes five small islands in Brittany: La Colombière, L’Ile aux Dames, Trevorc'h, l’Ile aux Moutons and le Petit Veizit.

OBJECTIVES

The main objective of the project was to enhance the breeding rate of Roseate Tern on L’île aux Dames and to re-attract this sea bird to four other neighbouring islands (la Colombière, Trevorc’h, l’île aux Moutons and Petit Veizit). The project had two specific objectives:

Increase the population by stabilising and optimising productivity (fluctuated from 0.1 to 1.3 fledged young between 1996 and 2003);

Increase the current distribution in Brittany to four more sites.

A management plan for each site will be established. Measures will be taken to reduce the impact of the various threats and disturbances. Potential predators, such as rats, rabbits, coypus and minks will be trapped and eradicated. The project will also ensure the presence of wardens during the Tern’s breeding period. By creating artificial colonies (using sound recordings and artificial stone nests), the project will enhance the probability of attracting new Tern colonies. Information programmes will be set up in order to heighten the awareness amonst local stakeholders and teh public of the issues of breeding sea-birds. The project will also contribute to improving the knowledge and management of this species in Europe amongst Natura 2000 site managers, amongst others by publishing a newsletter, organising an international workshop, producing a management guide and publishing the findings of the project.

RESULTS

The project was implemented without any major difficulties, apart from seasonal hazards – predation episodes and weather conditions that were not favourable to the installation of the bird colony. The beneficiary quickly adapted to unexpected events, such as repeated attacks by peregrine falcons, and the failure to control red foxes and to prevent American minks from attacking the colony.

However, the overall objectives of the project were not reached. In particular, the project was unable to reverse the decline of the breeding population. The mean production of fledged young per pair amounted to 0.48 between 2006 and 2010, while the objective was for it to exceed 0.50. The setting up of a network of four additional favourable sites was not completely achieved at the end of the project, even though two of the four sites – the Colombière and Moutons islets – are already being used by the species.

According to the project’s staff, these disappointing results can be explained by the repeated attacks of the colonies by American minks and peregrine falcons at key times of the breeding season. The peregrine falcon was not considered as an existing threat at the start of the project since it had not been observed in Brittany for over 40 years. Today predation and/or disturbances by the red fox, the American mink and the peregrine Falcon are considered the main threats facing the roseate tern.

The roseate tern colonies of Brittany, however, were maintained throughout the project duration. Additionally, the project showed that L’île aux Dames is still a very attractive site for the species and confirmed that La Colombière is also favourable to the species' installation. The successful breeding of one pair of roseate terns on L’île aux Moutons in 2010 is also encouraging given that this had not occurred since 1996.

According to the final report, a couple successfully bred in 2011 as well. Such results were achieved by:

Supervising the five project sites.

Raising the awareness of sea users.

Managing the habitats and, in particular, vegetation that is favourable to the roseate tern.

Controlling predators to prevent the colonies from being attacked.

Installing an operational photovoltaic system on L’île aux Moutons to replace the wind generator that was responsible for the death of several terns every year.

Erecting an impenetrable fence on L’île aux Dames to prevent further predation attacks by American minks.

Most recurrent actions of the project will have to be continued for the species to have a chance of surviving. Unfortunately, by the end of the project, the beneficiary did not succeed in securing the funding necessary for the full implementation of the after-LIFE conservation plan. According to the beneficiary, one of the top priorities is to reinforce the protection status of the sites, so that it can ensure the sustainability of the conservation actions and make it possible to obtain sufficient financial means. A meeting held in June 2011 with the French Ministry of Ecology was productive and a national action plan is now expected to be launched by 2013.

Further information on the project can be found in the project's layman report and After-LIFE Conservation Plan (see "Read more" section).