Andouin’s Gull

Vulnerable seagull finds refuge in Faro Islands

This month, Tomorrow’s wildlife column brings you the Andouin’s gull (Ichthyaetus audouinii), a bird currently classed as “vulnerable” on the IUCN red list of threatened species. The population of this friendly-looking gull has been declining globally in recent years, but in Portugal, Faro’s remote barrier islands have provided a much-needed sanctuary and ideal conditions for living and breeding. Barreta Island, also known as Isla Deserta (desert island), is currently home to the largest known colony of this species.

Named after the French naturalist Jean Victor Audouin (1797–1841), its genus name Ichthyaetus originates from ancient Greek and translates to “fish eagle” (ichthys = fish and aetus = eagle). This is an appropriate denomination as these seagulls feed nearly exclusively on fish. Unlike many of their seagull cousins, they tend to shy away from open-air dumpsites and bins and are not interested in nicking your waffles, fish and chips or your grilled sardines. In turn, Audouin’s gulls spend their days resting on rocky shores or sandy beaches, preferably away from human activity, and wait for dusk to come, when they fly out to the sea to hunt for fish. They are also known to follow fishing trawlers well into the night, knowing that unwanted bycatch represents easy meals.

An elegant and slim gull, it has the typical white body and grey wings that we are used to seeing in our other resident seagulls. A fraction smaller with a wingspan of 115–130 centimetres, it is more easily identified by its distinct dark eyes and a red bill with a black tip. They can live up to 20 years in the wild.

Audouin’s gulls live around the Mediterranean basin but also pass Gibraltar into Portugal and as far south as Senegal. Despite the generous distribution, these gulls are far more selective when it comes to choosing a nesting site. They require quiet, rocky areas or dunes with shrubby vegetation, far from human activity, feral animals, domestic pets and natural predators. This is precisely what they found on Barreta and more recently on the neighbouring island of Culatra. 

Back in 2019, the Portuguese Society for the Study of Birds – SPEA (BirdLife’s partner in Portugal) launched the Life Barrier Islands project that aimed to protect and monitor the unique ecosystem of this natural area. This year, the project counted over seven thousand nests, three times more than registered in the first year. These numbers represent the largest reproducing colony of the species today and a clear sign that Audouin’s seagulls feel at home here. SPEA is currently trying to secure the extension of the existing protected area to include a sea zone to promote the abundance of food, which is essential for this species to regain numbers. During years of abundance, females will lay three eggs, but less food availability can mean that pairs will only raise one chick or even decide not to lay at all. 

During the breeding season, which happens from April to August, individuals tend to stay near their colonies. However, from September onwards, many birds (not all) migrate to Africa for winter. This journey sees thousands of these seagulls passing through the Algarve and stopping shortly on our beaches and coastal lagoons before crossing the water. See if you can spot one this year!

You can help SPEA by becoming a member, donating or volunteering spea.pt/en

Fun facts

As mentioned in the article, these seagulls stay close to shore, around the Mediterranean perimeter. However, juvenile birds have been registered on single occasions in remarkable places such as the Azores (right in the middle of the Atlantic) and in Sheffield (UK)!