Kelp Gull

Appearance

The Kelp Gull superficially resembles two gulls from further north in the Atlantic Ocean the Lesser Black-backed Gull and the Great Black-backed Gull. The Kelp is intermediate in size between these two species. This species ranges from 54 to 65 cm in total length, from 128 to 142 cm in wingspan and from 540 to 1,390 g in weight.

Adult males and females weigh on average 1,000 g and 900 g respectively. Among standard measurements, the wing chord is 37.3 to 44.8 cm, the bill is 4.4 to 5.9 cm and the tarsus is 5.3 to 7.5 cm.

The adult Kelp Gull has black upperparts and wings. The head, underparts, tail and the small "mirrors" at the wing tips are white. The bill is yellow with a red spot, and the legs are greenish-yellow.

The call is a strident ''ki-och''. Juveniles have dull legs, a black bill, a dark band in the tail, and an overall grey-brown plumage densely edged whitish, but they rapidly get a pale base to the bill and largely white head and underparts. They take three or four years to reach maturity.

Behavior

Kelp Gulls are omnivores like most ''Larus'' gulls, and they will scavenge as well as seeking suitable small prey. It gathers on landfills and a sharp increase in its population is therefore considered as an indicator for a degraded environment. Kelp Gulls have been observed feeding on live right whales since at least 1996. The Kelp Gull uses its powerful beak to peck down centimetres into the skin and blubber, often leaving the whales with large open sores, some of which have been observed to be half a meter in diameter. This predatory behavior has been continually documented in Argentinian waters, and continues today. At rocky sites along the southern African coast, such as at Boulders Beach in Cape Town, Kelp Gulls can be seen picking up shellfish and repeatedly flying up several meters and dropping them onto the rocks below in order to break them open.