Malta’s seabirds face mounting pressures from light pollution and intensifying storms

Malta hosts regionally important seabird populations particularly of the Yelkouan Shearwater and the European Storm-petrel. These species are restricted to areas offering suitable nesting habitat – steep cliffs, offshore islets and sea caves. The Maltese Islands provide ideal conditions, with their limestone cliffs honeycombed by caves and fissures.

Human activity along the coast has increasingly confined shearwater colonies to more secluded sites. Light pollution and its far-reaching impacts have continued to reduce habitat quality in recent years. Shearwaters select darker sections of cliff, as an evolutionary adaption against avian predators, avoiding areas illuminated by bright lights.

At sunset, shearwaters gather in rafts offshore, waiting for darkness. Once night falls, they fly to their burrows, often accompanied by a distinctive vocal display. This behaviour is closely linked to lunar phases: shearwaters predominantly enter colonies before moonrise or after moonset along the moon cycle.

Rdum tal-Madonna – Photo John J. Borg

Although there is safety in numbers, higher colony densities resulting from habitat loss also bring disadvantages. Overcrowding can lead to territorial disputes between neighbours, sometimes resulting in damaged eggs. Inter-specific competition has also been observed, with the smaller Yelkouan shearwaters often at a disadvantage.

BirdLife Malta has sought to mitigate some of these pressures by installing artificial nest boxes for Yelkouan shearwaters. These provide dark, secure nesting spaces and have proved successful. Rat control has also been implemented to reduce predation by invasive alien species. In 2025, 17 nest boxes were occupied by breeding Yelkouan shearwaters. Since their introduction in 2014 more than 40 Yelkouan shearwaters have fledged from nest boxes at Rdum tal-Madonna alone. Currently, we are building on the successful uptake of nest boxes by Yelkouan shearwaters elsewhere, by attempting to establish the species on the islet of Fungus Rock, to support colonies at Dwejra, Gozo.

Yelkouan Shearwater chick – Photo Ben Metzger

However, increasingly intense storms pose an additional threat. Recent events, including Storm Harry, highlight the growing risk of larger and more frequent storm surges accelerating coastal erosion. Shearwaters are highly site-faithful: once a burrow is established, adults return year after year. Young shearwaters also tend to return to the same cave system from which they fledged. As storms damage cliffs and reduce available nesting habitat, birds may struggle to locate or establish new burrows. This impact is particularly evident at Rdum tal-Madonna, Malta’s largest Yelkouan shearwater colony, which supports over 500 pairs and has been severely affected by major storms in 1996, 2019 and now by Storm Harry.

Filfla has also been heavily impacted. Following decades of use as a British military target range, much of its shoreline consists of unstable rubble scree. While this habitat has proved suitable for nesting Storm-petrels – supporting the largest colony in the Mediterranean with approximately 8000 pairs – colony stability remains vulnerable. As stronger storms batter the exposed southern face of the islet, safeguarding the darker northern side from light pollution is essential to maintain favourable breeding conditions.

European Storm Petrel – Photo Aron Tanti

Seabirds can adapt over time, but only if given sufficient space and suitable conditions. Monitoring and research carried out by BirdLife Malta, amongst others, shows that Yelkouan shearwaters consistently avoid illuminated cliff sections and concentrate colony attendance during the darkest hours of the night, closely linked to lunar phase.

Artificial light alters natural patterns and increases the risk of disorientation. As coastal development intensifies and storms reshape nesting habitat, maintaining naturally dark coastlines throughout the entire night is therefore essential to safeguarding remaining habitat. Reducing coastal light pollution is a scientifically supported conservation priority for Malta’s internationally important seabird populations.

Martin Austad, Seabird Research Coordinator, BirdLife Malta 

 

Yelkouan Shearwater – Photo Luke Vella

RSS Feed Source: Independent Malta Malta’s seabirds face mounting pressures from light pollution and intensifying storms