Science Fair Project Encyclopedia
The Yellow-legged Gull, Larus cachinnans, is a large gull.
The taxonomy of the Herring Gull/Lesser Black-backed Gull complex is very complicated. This group has a ring distribution around the northern hemisphere. Differences between adjacent forms in this ring are fairly small, but by the time the circuit is completed, the end members, Herring Gull and Lesser Black-backed Gull, are clearly different species. However, different authorities recognise up to eight species in this complex.
It is has become fairly common to consider the Yellow-legged Gull as a full species, but there are still some problems. For example, the BOU in Great Britain places the Mediterranean form michahellis and the eastern cachinnans (Caspian Gull) in this species. However, recent DNA research has shown that Caspian Gull is basal to the complex, and cannot be in the same grouping as the other form.
Michahellis (named for the German zoologist Karl Michahelles) breeds in the Mediterranean, and there is a similar form atlantis on the Atlantic islands. These two forms are often considered as a good species, Larus michahellis, retaining the name "Yellow-legged Gull".
These birds are similar to Herring Gulls but have yellow legs. Western adults have a grey back, slightly darker than Herring Gull. They are much whiter-headed in autumn, and have more extensively black wing tips. They have a red spot on the bill like Herring Gull.
The Caspian Gull has back and wings more like the Herring Gull, but is a slimmer, more elegant bird with a more slender head. It is also white-headed in autumn.
These are omnivores like most Larus gulls, and they will scavenge on rubbish tips and elsewhere, as well as seeking suitable small prey in fields or on the coast, or robbing plovers or lapwings of their catches.
Eggs, usually three, are laid on the ground or cliff ledges in colonies, and are defended vigorously by this large gull. The call is a loud laugh.
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