10 Facts about seabirds

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Antarctic skua and gentoo penguin
© Chris Jonson/ WWF
Fascinating Facts

Seabirds are birds that spend some part of their lives living on and feeding in the sea. They include petrels, albatrosses, shearwaters, penguins, gannets, boobies, tropicbirds, frigatebirds, shags (or cormorants), auks, skuas, gulls, terns and noddies.

While a diverse group from different orders and families, they share some characteristics besides their habitat. Here are some things that seabird species have in common. 

Seabird capital of the world

Aotearoa New Zealand has the greatest number of resident seabird species, including many that are endemic. In addition, a third of all seabird species regularly visit our Exclusive Economic Zone (EEZ) during their non-breeding periods.

Long-lived

Despite a wide range of sizes and lifestyles, seabirds are generally slow to mature and breed, and long-lived. This can mean they struggle to adapt to changing environmental conditions compared to shorter-lived species that breed more frequently.

Colonies

Many seabirds are colonial, with a large number of species aggregating in loose or dense breeding colonies, where they find protection from predators through sheer numbers.

Good parents

Seabirds typically invest more time and effort into raising their young than land birds. Laying fewer eggs (sometimes one a year or even every two years) and taking care of them for longer. Both parents participate in caring for the young.

Strong bonds

Most seabirds mate monogamously, often staying together for multiple breeding seasons and in some cases for life. Divorce among seabird couples is not common, but does happen and is much more likely if they loses an egg or young chick.

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Catham albatross
© CJR Robertson

Chatham Island Albatross

Pops of colour

Most seabirds favour a subtle plumage in black, white or grey, but some like to mix in pops of colour. Around their heads and eyes, but particularly on their bills and legs. The bright yellow bill of the Chatham Island albatross pictured above being a great example. 

So salty

Seabirds can drink seawater (and eat salty prey) without ill effects. This is because the have special salt glands next to their eyes. These filter the excess salt which is excreted as a dense fluid that drips down their beaks. 

At risk

Seabirds are the most threatened group of birds globally. Almost half of all seabird species are known or suspected to be experiencing population declines.

Plasticosis

A new disease caused solely by plastics was discovered in seabirds in 2023. The birds identified as having the disease, named plasticosis, have scarred digestive tracts from ingesting waste. Over time, this can have knock-on effects on growth, digestion and survival.

Bycatch

Fisheries bycatch is the greatest threat to seabirds while at sea, often becoming hooked or entangled is fishing gear. Albatrosses and petrels are particularly impacted due to their large size and feeding behaviours. Mitigation methods can reduce the risks to seabirds from fisheries encounters.

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