Article contribution by Martin Austad
The jagged cliffs of the island are home to the Yelkouan shearwaters (Puffinus Yelkouan, MT: Garnija). This species of seabird is a regional endemic, breeding only in the Mediterranean basin. Almost 10% of the total population nests on the Maltese Islands, of which around 150-220 pairs are estimated on Kemmuna.
The Yelkouan shearwater gets its name from Turkish, yelkovan meaning the wind chaser. An adequate name for a seabird that spends its life whizzing over the waves in search of fish and squid. Shearwaters have long thin wings, suitable to glide on the wind over the sea surface. It is also appropriate that the species gets its name from the Turkish language, as thousands of Yelkouan shearwaters pass through the Bosphorus and Dardanelles Straits to and from the Black Sea, where they spend their non-breeding period.
Back to Kemmuna, during the breeding season shearwaters seek deep burrows safe from natural predators such as the Yellow-legged gull and Peregrine falcon. The limestone cliffs have many suitable nesting crevices to offer, and if the top spots are full, there is always spaces to find between boulders in the screes below the cliffs. The cliffs of Kemmunett, the cliffs below Santa Marija Tower and the caves and cliffs on the north-east of Kemmuna are particular favourites with the species. The shearwaters have another adaptation against avian predators, which is to return to their colonies only at night in the cover of darkness. This behaviour is even fine tuned to the moon cycle but is jeopardised by light pollution. Excessive light reaching the cliffs makes the shearwaters wary of predators continuing to hunt through the night, and some might not enter their nests at all[1]. The strong and poorly angled lights at Ċirkewwa and Mġarr ferry terminals, as well as Ħondoq ir-Rummien and the increasing sky glow are of particular concern. Lights and noise from the multitude of vessels along the coastline add on to the disturbance, but damage to the main colonies can be limited by keeping to the Notice to Mariners 9 of 2023[2].
The adaptations shearwaters have against avian predators are useless against introduced mammals for which evolution has not prepared them. Rodents, especially the Black rat, are the most widespread and damaging, preying on the shearwater eggs and nestlings. Each shearwater pair only has one chick per year, because raising offspring on a marine diet is so demanding and unpredictable. As a result, the effect of high nest predation by invasive species can be devastating on a population. BirdLife Malta has been carrying out seasonal rodent control on Kemmunett and the east cliffs of Kemmuna since 2018[3], following the successful methods developed at L-Irdum tal-Madonna since 2007[4]. Complete rat eradication is not possible on Kemmuna due to the proximity to Għawdex (rats are good swimmers) and the large numbers of boats posing a biosecurity risk on a daily basis. Therefore, seasonal measures at least ensure that Yelkouan shearwaters can nest with minimal predation pressure, while avoiding risks to other species. Waste management practices have a key role to play too, in order to make sure that rodent populations are not elevated by littered organic waste, especially left overnight.
The Yelkouan shearwater nesting season is long. The single white egg is laid in February-March, after what is called the pre-laying exodus, when females spend two weeks at sea foraging and building up resources to produce the egg[5]. Incubation lasts another 50 days, with both male and female taking turns on the egg, each shift lasting several days! The work has only just started, because once the egg hatch, both parents need to feed the chick for around 70 days. The shorter foraging trips are made within Maltese waters and also to the south of Sicilly, but Maltese Yelkouan shearwaters regularly travel all the way to the Gulf of Gabes in Tunisia. Not only are they willing to take on long commutes, they also make extraordinary dives and underwater persuits to get their food. Tagging shearwaters with depth loggers showed that Yelkouan shearwaters regularly went deeper than 30m and the record dive was 51.6m[6]! Pelagic fish such as Horse Mackarel and Anchovy are high on the menu but overfishing of fish stocks causes shearwaters to follow fishing vessels in hope for an alternative meal. It is a risky strategy that can lead to fatal bycatch incidents, especially when they go for baited hooks.
For the young shearwaters the biggest adventure still lies ahead. On the first nights of summer, they fledge all alone, leaping from cliff ledges and finding their ability to fly and navigate the open ocean, their new home[7]. Here too, light pollution comes as a threat, confusing the young birds resulting in some ending up in urban areas instead of at sea. Unless rescued, they risk getting run over or preyed on by feral cats. For those shearwaters that survive the first perilous years at sea, the cliffs of Kemmuna are waiting to welcome them yet again, because indeed these incredible birds find their way back to the very ledges where they themselves hatched.
If you have made it this far down the article you deserve to know how to be able to appreciate this species for yourself, but then you need to be ready for a challenge! They can be spotted from land in the evening as they gather in flocks, waiting for darkness in the safety of numbers. The channel between Malta and Gozo is a good spot, look out for compact flocks of birds flying low over the waves with fast wingbeats. The dark upperparts and white underparts are characteristic, especially when they change flight direction. The true spectacle is to be enjoyed at night however, but take care not to disturb the birds and use a torch with red light at the cliffs. On any clear calm starry night, especially in February, you can enjoy a cacophony of bizarre shearwater calls from the cliffs as they fend off competitors or to attract a partner.
Together we might see the Yelkouan shearwater connecting the sea and land through its fascinating behaviour for many generations to come.
Martin Austad
BirdLife Malta Seabird Research Coordinator
June 2025
[1] https://link.springer.com/article/10.1007/s10336-023-02045-z
[2] https://www.transport.gov.mt/include/filestreaming.asp?fileid=8435
[3] https://birdlifemalta.org/wp-content/uploads/2020/10/Birdlife-Report-English-Digital_V3.pdf
[4] https://birdlifemalta.org/wp-content/uploads/2015/04/Yelkouan-Shearwater-Project-Layman%E2%80%99s-report-EN.pdf
[5] https://link.springer.com/article/10.1007/s10336-019-01646-x
[6] https://lifepanpuffinus.org/wp-content/uploads/2024/09/Diving-into-yelkouan-shearwater-foraging-behaviour-with-time-depth-recorders.pdf
[7] https://www.researchgate.net/publication/383466678_High-resolution_tracking_of_fledged_Yelkouan_Shearwaters_Puffinus_yelkouan_exposes_post-fledging_migration#fullTextFileContent
