The science
Genetics & Evolution
Seabirds are not one family. Life at sea evolved several times, in different lines of birds.
Convergent evolution
Penguins, auks, albatrosses and gannets are not closely related, yet many share similar features. The same challenges, such as salty water, cold seas and patchy food, have shaped them in similar ways. This is known as convergent evolution. Auks of the north and penguins of the south are a classic example.
Deep history
The first seabirds appeared during the Cretaceous period. Modern seabird families emerged after the dinosaurs, in the Paleogene. Fossils include giant penguins as tall as a person and pelagornithids, extinct birds with bony, tooth-like projections on their bills and wingspans that may have exceeded 6 m.
DNA rewrites the family tree
Genetic studies have reshaped seabird classification. Birds once grouped together because all four toes are webbed, such as cormorants, gannets, frigatebirds, pelicans and tropicbirds, turned out to belong to three separate orders.
Genetics in conservation
DNA is now a practical field tool. It can reveal a bird's sex, link birds to their home colony, separate cryptic species that look identical, and measure how isolated a population is.
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