What is a seabird? (1 Viewer)

This might be a strange thing to ask, but how exactly is a seabird defined?

Does it include all the gulls and terns? The reason I ask is that a book I'm reading (Penguin by Stephen Martin) mentions that there are only 300 species of seabird in the world, and I was struck by how low this figure is.

JTweedie said:

This might be a strange thing to ask, but how exactly is a seabird defined? Does it include all the gulls and terns? The reason I ask is that a book I'm reading (Penguin by Stephen Martin) mentions that there are only 300 species of seabird in the world, and I was struck by how low this figure is.

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Most popular terms in ornithology are general terms, for a simple reason - language is too limited to produce exact definitions. Almost all familes or species-groups have exceptions eg amongst the gulls there are several species that scarcely ever come near the sea (the word 'seagull' is a fundamental misnomer!), and amongst the terns, those described as 'river terns' are clear exceptions to inclusion as seabirds.

A Dictionary of Birds by Bruce Campbell and Elizabeth Lack (1985 T&AD Poyser) carefully avoids including 'seabird' as a term to be defined. All the books in my possession that have 'seabird' in their titles either assume that the birds included are known as seabirds, or justify the included species with reasons that may be obvious or acknowledge the broad or narrow view taken!
MJB
PS As my Auntie Alice would have said, 'It's a richt scunner!'.B

I'm careful not to say seagull either, but it's still a term used by non-birders, especially in the press. With herring and lesser black-backed gulls moving inland more to occupy rubbish tips etc, we may get to stage where the label "sea" won't be applicable to them.

Another gull I see more inland than at sea is the black-headed gull, it's very rare if I see one on the coast.

In his seminal "Seabirds, a Guide to Identification", Peter Harrison defines seabirds as "species whose normal habitat and food source is the sea...". However, he also includes all members of taxa which include such birds.

He therefore, rather curiously, includes birds such as Aititlan Grebe, a virtually flightless species endemic to a lake in Guatemala (and sadly now extinct).

As MJB says, "seabird" is a loosely defined term which means different things to different people &, in some cases, to the same people in different contexts. In that respect, it's very like "bird of prey" the meaning of which was hotly debated not too long ago in another thread.

Edit: Here's the BOP thread I was referring to: http://www.birdforum.net/showthread.php?t=191568&highlight=The+Grey+Heron

As you can see, it goes round & round before petering out with no consensus in sight.

DMW said:

In his seminal "Seabirds, a Guide to Identification", Peter Harrison defines seabirds as "species whose normal habitat and food source is the sea...". However, he also includes all members of taxa which include such birds.

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But Harrison notably excluded sea-ducks (except for three pages of line drawings), which are more deserving of the description 'seabird' than several of the species included. However it arguably makes sense for such guides to include all members of the families treated, and Helm had a complementary Wildfowl guide (Madge & Burn) in the pipeline...