Hartlaub’s Gull (Chroicocephalus hartlaubii)

Hartlaub's Gull

Identification

If you are in the Western Cape, and the seagull has grey wings, then with safety** you can call it a Hartlaub’s Gull. If the back is black, it’s almost certainly a Kelp Gull.

Identification guide to adult Hartlaub's Gull

Young Hartlaub’s Gulls have a brown pattern on the feathers on the back. These patterned feathers get replaced one by one during the first year or so, and the birds then have plain grey wings like the adults.

Identification guide to juvenile Hartlaub's Gull

Listen to the call of the Hartlaub’s Gull.

** The level of “safety” in the Western Cape is about 99.9%! There are only handfuls of a closely related species, the Grey-headed Gull, in the Western Cape. But what is even worse is that these two gulls interbreed. So there are some hybrids in the mix. This is what makes birding fascinating.

On the Namibian coastline there are more Hartlaub’s Gulls than Grey-headed Gulls (and quite a lot of hybrids). In the Eastern Cape most of the gulls are Grey-headed. In KwaZulu-Natal, Hartlaub’s Gull is a rare vagrant.

Habitat

Mainly on the coastline, and at wetlands close to the coast.

Distribution

Annotated SABAP2 distribution map for Hartlaub's Gull
SABAP2 distribution map, downloaded 14 June 2021

In Namibia, they occur almost anywhere along the coast; most are in the Lüderitz area, and along the coastline from Walvis Bay Lagoon northwards to Swakopmund.

Gallery

This is the easternmost record of Hartlaub’s Gull in the Virtual Museum, within the normal range. Farther east, there are two records in KwaZulu-Natal, where it is recorded from time to time. This photo was taken on the Swartkops Estuary, Algoa Bay:

The easternmost record of Hartlaub's Gull in the Virtual Museum, in KwaZulu-Natal, South Africa
BirdPix record of Hartlaub’s Gull, in the Eastern Cape

The two KwaZulu-Natal records can be viewed here and here!

And below is the northernmost record of Hartlaub’s Gull in the Virtual Museum. The bird was at the Mile 4 Saltworks, which is (well, obviously) four miles north of Swakopmund, in Namibia. This is the limit of the regular range of this species. Farther north, they occur just occasionally. This photo shows a young bird, with the juvenile feathers on the wing coverts mostly replaced by the plain grey adult feathers. There is also one brown-tipped flight feather left in the wing. The bill and legs are near the black end of the red to black continuum.

Hartlaub's Gull
Northernmost BirdPix record of Hartlaub’s Gull, at Mile 4 Saltworks, just north of Swakopmund, Namibia. It is a young bird. Photo Etienne Marais

Hartlaub’s Gulls mostly breed in large colonies on the offshore islands; sometimes the colonies consist of thousands of pairs of birds:

'Hartlaub's Gull breeding colony on Robben Island

This colony was on Robben Island in June 2014. Hartlaub’s breed in autumn and winter. Gull colonies are noisy places!

Further resources: A selection of papers

More common names: Hartlaubse meeu (Afrikaans), Mouette de Hartlaub (French), Hartlaubmöwe (German), Gaivota de Hartlaub (Portuguese), Gaviota plateada surafricana (Spanish)

Photographic acknowledgements: Most of the photographs in this identification guide are from the BDI Virtual Museum. The photographers continue to own the copyright on these images.

List of bird species in this format is available here.

Recommended citation format: Underhill LG 2023. Hartlaub’s Gull Chroicocephalus hartlaubii. Biodiversity and Development Institute. Available online at https://thebdi.org/2023/03/12/hartlaubs-gull-chroicocephalus-hartlaubii/.

Les Underhill
Les Underhill
Prof Les Underhill was Director of the Animal Demography Unit (ADU) at the University of Cape Town from its start in 1991 until he retired. Although citizen science in biology is Les’s passion, his academic background is in mathematical statistics. He was awarded his PhD in abstract multivariate analyses in 1973 at UCT and what he likes to say about his PhD is that he solved a problem that no one has ever had. He soon grasped that this was not the field to which he wanted to devote his life, so he retrained himself as an applied statistician, solving real-world problems.