Why are there fewer and fewer gulls in Brittany? – Brittany

How can you imagine the Breton coast without the gull? Without its shrill cry, its yellow, hooked beak, and its keen gaze, fixed on your sandwich and on the smallest crumb that you could drop? Madeleine de Proust for some, bad memories for others, this emblematic animal has become inseparable from Brittany. If the population often imagines that the number of gulls continues to grow, this is a misleading vision, biased by an urban perspective.

Last February, the Bretagne Vivante association published a report on breeding bird populations in Brittany. Their observation is simple: two of the three species of gulls, living in the wild, will soon be considered vulnerable, and therefore threatened, on the regional red list.

In 10 years, 45% fewer brown gulls

The data is instructive. Brown gull and herring gull populations in the wild have dropped drastically since 2010. The latter, already classified as vulnerable on the regional red list, has lost 28% of its population over the past decade, establishing today at nearly 14,000 breeding pairs, against nearly 40,000 in 2000.

The situation for the brown gull is worse. In ten years, the decline reached 45% for the region, and 71% in Finistère, the most affected department. The situation of Côtes-d’Armor, in growth, is only the reflection “of a change in census method, thanks to drones”, and therefore of a “upgrading of data”, as explained by Yann Juillet , ornithologist and director of Geoca.

The black-backed gull, described as a “super predator” by Bernard Cadiou, ornithologist at Bretagne Vivante, has suffered fewer losses over the past decade, thanks to less dependence on humans. However, this bird, a hunter of other gulls, therefore suffered from their significant decline.

Why such a drop?

Different factors explain this fall, but food is the main cause. As Bernard Cadiou explains, the 70s and 80s were conducive to the growth of gull colonies. The lack of regulation on fishing discards and open-air recycling centers offered a feast to these birds, qualified as “airborne garbage collectors”, and allowed their development. These “baby boomers”, as the ornithologist calls them, born in the 80s and 90s, had a life expectancy of almost 30 years. In the meantime, human resources have become scarce, and so have birth rates. A peak in mortality therefore occurred between 2010 and today, without the populations renewing themselves.

Surprisingly, the births recorded in Cap Fréhel (22) show a halving of the number of young gulls, for the year 2020. Bretagne Vivante cannot guarantee this, but the health restrictions linked to covid, and consequently , the absence of hikers and picnics, “strangely coincide” with these censuses.

Migrations in the cities

In search of food, the gulls have logically taken refuge in the cities (for lack of means, the censuses of urban gulls could not be carried out). For several decades, some municipalities have been carrying out gull egg sterilization operations. For Bernard Cadiou, this type of action, carried out under authorization, works in an ephemeral way, because the birds are constantly changing their laying location: “We are moving the problem”, he explains. For Lionel Richard, head of sterilization campaigns in Brest, these operations are essential to “regulate urban populations before they become harmful”.