New (overlooked) record for Botswana bird list?

During the Peterhouse School scientific expeditions to Botswana between 1966 and 1970, schoolchildren under the supervision of Peter Ginn (well-known as the editor of ‘A Complete Book of Southern African Birds’) collected bird specimens from the Makgadikgadi area. During one of these outings, a gull that was collected in the Nata area, in the company of Grey-headed Gulls, turned out to be an exciting find. Once the group had returned to Zimbabwe, the gull was tentatively identified by Mr Stuart Irwin from the Natural History Museum as Larus novaehollandiae. This was subsequently confirmed by Messrs CW Benson and PR Colston at the British Museum of Natural History.

When Larus novaehollandiae was later split, the nominate race in Australia retained the name L. novaehollandiae and the southern African birds became L. hartlaubii. This species is restricted as a breeding bird to the coldwater coasts of Namibia and the Western Cape, and sightings inland are quite unusual.

However the interesting thing about this observation is that Larus hartlaubii does not feature on the Botswana bird list. There is no mention of it in the Bird Atlas of Botswana – this ‘bible’ for birds in Botswana included historical data on our birds as well as observations spanning the decade 1980 to 1990. Could this species have been overlooked?

It would be interesting to know the whereabouts of the specimen collected by the Peterhouse expedition, to confirm its identity. Anyone who knows anything about this observation is invited to comment below.