Page 464 - Atlas Sea Birds Ver1

3.10 Numbers, trends, status, conservation, and management
of Kelp Gull (Larus dominicanus) in southern Africa

Authors: RJM Crawford, AP Martin, M Morais, DB Tom, PA Whittington, M Witteveen, BM Dyer, M Masotla, L Upfold, and AB Makhado

Abstract:
The subspecies vetula of Kelp Gull (Larus dominicanus) is endemic to southern Africa, where it bred coastally at 127 sites in the Benguela
upwelling ecosystem (BUS) from Ilha dos Tigres in southern Angola to the Nculura River mouth, east of Woody Cape on South Africa’s
south coast. The species’ global and regional Red List classification is Least Concern. The southern African population increased from
c. 11,200 pairs in 1976–1981 to > 21,000 pairs from 2000–2004 and then decreased to 14,000–16,000 pairs from 2018–2022. The
increase in Kelp Gulls in the latter part of the 20 century was attributed to the cessation of controls on Kelp Gulls breeding at islands off
th
South Africa’s west coast and to the provision of supplementary food at fishing harbours and rubbish tips. Predation of chicks by Great
White Pelicans (Pelecanus onocrotalus) later caused decreases at the same islands. Kelp Gulls were able to relocate breeding to other,
including mainland, sites and there was growth of numbers at southern colonies. Control of Kelp Gull numbers has been reinstated at
some islands due to Kelp Gull predation of eggs and chicks of threatened seabirds that are endemic to BUS. This will have contributed to
the recent decrease of southern African Kelp Gulls.

Introduction:
The Kelp Gull (Larus dominicanus) is widely distributed in the southern hemisphere, breeding in southern Africa, south Madagascar,
southern Australia, New Zealand, around South America from northern Peru in the Pacific Ocean to southern Brazil in the Atlantic Ocean,
at subantarctic islands, and in Antarctica (Del Hoyo et al. 1996). In 2014, the global population of Kelp Gulls was estimated to number
3.3 to 4.3 million birds, to be increasing, and its Red List status, in terms of criteria of the International Union for Conservation of Nature
(IUCN), was Least Concern (LC) (Whittington et al. 2016). It was also regarded as LC in Namibia and South Africa (Simmons et al. 2015,
Taylor et al. 2015).
Kelp Gulls in southern Africa were recognised as a distinct subspecies (L. d. vetula) (Brooke and Cooper 1979). They bred almost
exclusively at coastal sites within the Benguela upwelling ecosystem (BUS), which ranges from Benguela in south Angola to Woody
Cape at the east of Algoa Bay in southern South Africa (Figure 1). One to two pairs of Kelp Gulls were recorded nesting at three sites
farther east, between Woody Cape and Hamburg, each on one occasion, and are the most eastern records of breeding by this species in
southern Africa (Whittington and Crawford 2024).
This chapter updates information on numbers of Kelp Gulls breeding in southern Africa and their distribution. It identifies present
important breeding areas for the species and briefly considers factors that may affect their numbers.

Numbers and distribution maxima between 1,000 and 2,000 pairs and 26 sites had
maxima between 100 and 957 pairs (Table 2).
Records of breeding by Kelp Gulls at coastal sites in In Angola, 954 pairs of Kelp Gull bred at Ilha dos
Angola, Namibia, and South Africa in different years from Tigres in 2005 (Table 2, Dyer 2007). The colony has not
1755–2022 are shown in Table 1. Information was collated subsequently been censused but Kelp Gulls still bred there
from Crawford et al. (1982, 2009), Steele and Hockey in 2020 (Morais 2024).
(1990), Du Toit et al. (2003), Whittington et al. (2006b, In Namibia, 2,293 pairs of Kelp Gulls bred at 18 sites
2016), Dyer (2007), Kemper et al. (2007), Witteveen (2015), from 1976–1981 (Table 2, Crawford et al. 1982) and 2,497
and relevant breeding locality chapters in this volume. were thought to breed c. 2007 (Kemper et al. 2007). About
When multiple counts were obtained at a locality in a given 1,500 pairs bred at Possession Island in 2006 but that
year, the maximum was used. When a range was given, colony has not been counted since then. The sum of the
the mid-point was used. ‘√’ signifies that breeding occurred most recent count of Kelp Gulls at each Namibian breeding
at a locality but the numbers were not ascertained; ‘?’ that locality was 2,336 pairs (Table 2). These values suggest the
breeding may have taken place. In southern Africa, Kelp Namibian population is of the order of 2,300–2,500 pairs.
Gulls bred in the austral summer, with laying recorded from However, more up-to-date counts of numbers at breeding
September to January and replacement clutches up to colonies would be useful.
February (Crawford and Hockey 2005). Years indicated in
Tables 1 and 2 and in text that makes mention of the period
of breeding refer to the first year in the split year breeding
season.
Kelp Gulls were recorded nesting at 127 sites in southern
Africa, of which one was in Angola, 28 were in Namibia, and
98 were in South Africa (Figure 1). Twenty-nine of the sites
had only solitary pairs. Five sites at some stage held > 2,000
pairs: Dassen, Schaapen, Robben, Jutten, and Meeuw
islands had maxima of 6,406 pairs, 6,225 pairs, 3,395
pairs, 2,582 pairs, and 2,215 pairs, respectively. These
sites all lie between Saldanha Bay and Cape Town. Five
other sites (Possession Island in south Namibia, Velddrift
Saltworks in St Helena Bay, Strandfontein coastline and
Wolfgat Nature Reserve on the northern False Bay coast,
and the Keurbooms Peninsula near Plettenberg Bay) had A nesting Kelp Gull (photo BM Dyer)

458