Larus hartlaubii (Harlaub's Gull)

Larus hartlaubii (Hartlaub's Gull)

Hartlaubse meeu [Afrikaans]; Sterretjie [Afrikaans]; Mouette de Hartlaub [French]; Hartlaubsmöwe, Weißkopflachmöwe [German]; Gaivota de Hartlaub [Portuguese]

Life > Eukaryotes > Opisthokonta > Metazoa (animals) > Bilateria > Deuterostomia > Chordata > Craniata > Vertebrata (vertebrates) > Gnathostomata (jawed vertebrates) > Teleostomi (teleost fish) > Osteichthyes (bony fish) > Class: Sarcopterygii (lobe-finned fish) > Stegocephalia (terrestrial vertebrates) > Tetrapoda (four-legged vertebrates) > Reptiliomorpha > Amniota > Reptilia (reptiles) > Romeriida > Diapsida > Archosauromorpha > Archosauria > Dinosauria (dinosaurs) > Saurischia > Theropoda (bipedal predatory dinosaurs) > Coelurosauria > Maniraptora > Aves (birds) > Order: Charadriiformes > Family: Laridae > Genus: Larus


Hartlaub's gull, Cape Peninsula National Park, Western Cape, South Africa. [photo Duncan Robertson ©]	Hartlaub's gull, Strandfontein Sewerage Works, Western Cape, South Africa. [photo Duncan Robertson ©]

Distribution and habitat

Endemic to southern Africa, occurring along of the coast of Namibia (up to Cape Cross) and the Northern and Western Cape, largely coinciding with the distribution of the kelps Laminaria pallida and Ecklonia maxima. It generally prefers coastal habitats, especially if disturbed by human activity, in fact approximately half of its population occurs in man-made areas.

Distribution of Hartlaub's gull in southern Africa, based on statistical smoothing of the records from first SA Bird Atlas Project (© Animal Demography unit, University of Cape Town; smoothing by Birgit Erni and Francesca Little). Colours range from dark blue (most common) through to yellow (least common). See here for the latest distribution from the SABAP2.

Predators and parasites

Predators
- of adults
  - Larus dominicanus (Kelp gull)
  - Catharacta antarctica (Subantarctic skua)
- of eggs
  - Galerella pulverulenta (Small grey mongoose)
  - Cynictis penicillata (Yellow mongoose)
- of chicks
  - Bubulcus ibis (Cattle egret)
  - Felis catus (Domestic cat)
  - Larus dominicanus (Kelp Gull)
- of eggs and chicks
  - other Grey-headed gulls
  - Threskiornis aethiopicus (Sacred ibis)
  - Pseudapsis cana (Mole snake)
Parasites
- shistosomes
  - Austrobilharzia
  - Gigantobilharzia

Movements and migrations

Generally sedentary, although juveniles from island colonies disperse across the sea to the mainland.

Food

It mainly eats fish and aquatic invertebrates, doing most of its foraging by seizing prey from the water surface while swimming, plunge-diving, scavenging in the wake of trawlers, plucking food from the ground or hawking termite alates aerially. The following food items have been recorded in its diet:

Vertebrates
- fish
  - Lampanyctodes hectoris (Lantern fish)
  - Sugglogobius bibarbatus (Pelagic goby)
  - Engraulis encrasicolus (Cape anchovy)
  - Sardinops sagax (Sardine)
  - Merluccius (hakes)
  - Thrysites atun (Snoek)
- eggs
- Bradypodium pumilum (Cape dwarf chameleon)
Invertebrates
- Nereis (polychaetes)
- molluscs
  - Sepia australis (Southern cuttlefish)
  - Tricolia capensis (Pheasant shell)
  - Fissurella mutabilis (Cape keyhole limpet)
  - Nodolittorina africana (African periwinkle)
  - Dendrofissurella scutella (Saddle-shaped keyhole limpet)
  - Donax serra (White mussel)
  - Mytilus galloprovincialis (Mediterranean mussel)
- arthropods
  - Talorchestia capensis (Beach hopper)
  - Ligia glabrata (Sea-slater)
  - Deto echinata (Horned isopod)
  - Paridotea reticulata (Reticulate kelp louse)
  - Upogebia capensis (Coastal mudprawn)
  - Jasus lalandii (West coast rock lobster)
  - Plagusia chabrus (Cape rock crab)
  - Ovalipes trimaculatus (Three-spot swimming crab)
  - insects
    - fly larvae and pupae (Diptera)
    - tettigonid grasshoppers (Orthoptera)
    - Coleoptera (beetles)
    - ants
    - coraxids
- earthworms
Other
- domestic waster (of plants and animals)
- fruit of low-growing shrubs

Breeding

Monogamous colonial nester, with each pair defending a small territory around the nest, defending it by performing aggressive displays.
The nest (see image below) is an untidy bowl of plant stems, typically placed on rocky ground or alternatively among reeds or on a man-made structure, such as guano platforms, buildings, roofs, dam walls and flower pots.


Hartlaub's gull nest with eggs, Velddrif, South Africa. [photo Warwick Tarboton ©]

Egg-laying season is mainly from March-June in Namibia, and from January-October, peaking from February-April in the Western Cape, although it may breed at any time of year depending on environmental conditions.
It lays 1-3 eggs, which are incubated by both sexes for about 25 days.
The chicks are fed by both parents by regurgitation; if a snake approaches the young, the adults attack the intruder.

Threats

Not threatened, in fact its population greatly increased due to human disturbance, although it is now thought to be either stable or decreasing.

References

Hockey PAR, Dean WRJ and Ryan PG 2005. Roberts - Birds of southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town.