Page 51 - Atlas Sea Birds Ver1

2.2.1 Introduction to seabird breeding locality chapters

Fifteen species of seabird are known to have bred in Angola, Namibia, or South Africa, where they have been recorded nesting at 369
localities around the coasts of these countries. The localities are briefly described in the following 26 chapters, which start with sites in
Angola and then follow the shoreline around southern Africa to conclude with those in KwaZulu-Natal in northeast South Africa.

For each locality, its coordinates, habitat, and conserva- The sources of all published counts are indicated in
tion status were indicated and seabirds that were recorded each chapter so that readers will be able to examine origi-
breeding at it were listed. For each seabird species and nal records as necessary. Unpublished information has
calendar year having abundance information, the largest also been included and was collected in a similar manner
count or estimate of the number of pairs breeding was to that listed in previous species assessments, which are
listed. Sometimes estimates of numbers were given as indicated in the accounts of the breeding seabirds of the
ranges. In such instances the mid-points of ranges were Benguela ecosystem and adjacent regions that follow the
often provided. Some seabirds in the Benguela eco- chapters on breeding localities.
system and adjacent areas breed in the austral summer
and have a breeding season that spans across calendar References
years (Hockey et al. 2005). However, because for several
early counts only the year of breeding was recorded (e.g. Braby J. 2011. The biology and conservation of the Damara Tern in
Rand 1963), and the split-year breeding season could Namibia. PhD thesis. University of Cape Town, South Africa,
not be determined, in the following chapters maxima were 233 pp.
usually given for calendar years, but not for a survey of Brooke RK, Cooper J, Shelton PA, Crawford RJM. 1982. Taxonomy,
Damara Terns undertaken in 2021/22 (Kolberg 2022). For distribution, population size, breeding and conservation of
species which have split-year breeding, the year shown the White-breasted Cormorant, Phalacrocorax carbo, on the
is that in which breeding starts. southern African coast. Le Gerfaut 72: 189–220.
Some published accounts gave numbers of nests (e.g. Cooper J. 1981. Biology of the Bank Cormorant. 1. Distribution,
Rand 1963) or nest sites (e.g. Cooper 1981), whereas population size, movements and conservation. Ostrich 52:
others additionally included pairs without nests that were 208–215.
defending territory and/or pairs represented by chicks in Crawford RJM, Williams AJ, Hofmeyr JH, Klages NTW, Randall
RM, Cooper J, Dyer BM, Chesselet Y. 1995. Trends of
creches (e.g. Williams et al. 1990, Crawford et al. 1995, African Penguin Spheniscus demersus populations in the
Underhill et al. 2006). Therefore, definitions of pairs var- 20th century. South African Journal of Marine Science 16:
ied between studies. Some counts of numbers of seabirds 101–118.
breeding were made on visits to localities. Others were Crawford RJM, Dyer BM, Upfold L. 1999. Seasonal pattern of
made on, or estimated from, aerial photographs taken of breeding by Cape and Crowned Cormorants off western
localities (e.g. Rand 1963, Sherley et al. 2019). For spe- South Africa. Ostrich 70: 193–195.
cies having cryptic nests, such as some terns, on occasion Crawford RJM, Kemper J, Underhill LG. 2013a. African Penguin
numbers of pairs were gauged from counts of adult birds (Spheniscus demersus). In: Garcia Borboroglu P, Boersma
(e.g. Braby 2011). PD (eds). Penguins Natural History and Conservation.
All seabirds breeding in the Benguela ecosystem are to University of Washington Press, Seattle and London, pp.
211–231.
a greater or lesser extent seasonal breeders (Hockey et al. Crawford RJM, Randall RM, Whittington PA, Waller LJ, Dyer BM,
2005). However, the season of breeding may vary between Allan DG, Fox C, Martin AP, Upfold L, Visagie J, Bachoo
species and, within species, between localities (e.g. Craw- S, Bowker M, Downs CT, Fox R, Huisamen J, Makhado AB,
ford et al. 1999, 2013a, 2013b). Furthermore, birds may Oosthuizen WH, Ryan PG, Taylor RH, Turpie JK. 2013b.
abandon nesting early in a breeding season (e.g. Randall South Africa’s coastal-breeding white-breasted cormorants:
and Randall 1981), or the peak of breeding at a locality population trends, breeding season and movements, and
may vary between years (e.g. Crawford et al. 1999). Some diet. African Journal of Marine Science 35: 473–490.
breeding localities are remote or difficult to access or ex- Hockey PAR, Dean WRJ, Ryan PG (eds). 2005. Roberts Birds of
Southern Africa, 7th Edition. John Voelcker Bird Book Fund,
pensive to survey, so that their seabird populations were Cape Town.
infrequently counted (e.g. Mendelsohn and Haraes 2018) Kolberg H. 2022. Report on a Damara Tern breeding survey along
and surveys may have missed breeding peaks. the Namibian coast. Ministry of Environment, Forestry and
Given these limitations to the counts and the manner Tourism, Namibia, unpublished report: 5 pp.
in which they were obtained, care should be taken when Mendelsohn JM, Haraes L. 2018. Aerial census of Cape
using them to estimate sizes of, or trends in, populations. Cormorants and Cape Fur Seals at Baía dos Tigres, Angola.
For species that nest at just a few localities and are ame- Namibian Journal of Environment 2 A: 1–6.
nable to census techniques such as aerial photography, for Rand RW. 1963. The biology of guano-producing seabirds.
example gannets, it has been possible to estimate annual 4: Composition of colonies on the Cape islands. In-
trends in abundance (e.g. Sherley et al. 2019). For more vestigational Report Sea Fisheries Research Institute South
Africa 43: 1–32.
widely-dispersed species, as some cormorants, gulls, and Randall RM, Randall BM. 1981. The annual cycle of the Jackass
terns, it has proved difficult to conduct complete censuses Penguin Spheniscus demersus at St. Croix Island, South
annually. Therefore, their populations have often been Africa. In: Cooper J (ed.). Proceedings of the Symposium
assessed over, and compared between, periods of several of Birds of the Sea and Shore. African Seabird Group, Cape
years (e.g. Brooke et al. 1982, Crawford et al. 2013b). Town: pp. 427–450.

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