Page 447 - Atlas Sea Birds Ver1

3.9 Numbers, trends, status, and conservation of Crowned
Cormorant (Microcarbo coronatus)

Authors: RJM Crawford, BM Dyer, M Masotla, DB Tom, L Upfold, JL Visagie, and AB Makhado

Abstract:
Crowned Cormorants (Microcarbo coronatus) are endemic to the Benguela upwelling ecosystem, where they have bred at 72 sites between
Bird Rock Platform in central Namibia and No. 12 Stack in the Tsitsikamma section of Garden Route National Park in southern South
Africa. The overall numbers breeding were 2,665 pairs from 1977–1981, 2,345 pairs from 1995–2006, 2,748 pairs from 2013–2017, and
2,657 from 2018–2022, when 44% were in Namibia and 56% in South Africa. The species’ population has therefore been stable and is
not Threatened in terms of criteria of the International Union for Conservation of Nature. However, its population is small (< 6,000 mature
individuals) and in 2015 it was considered Near Threatened in both Namibia and South Africa. Numbers recently decreased by 25% in
five years in South Africa and the species should continue to be regarded at Near Threatened there. Between 2018 and 2022, or at their
most recent visit, nine sites held ≥ 100 pairs and should be regarded as important breeding sites for the species. Threats to Crowned Cor-
morants include human disturbance at breeding sites, loss of breeding habitat, mortality resulting from incorporation of human debris into
nests, oiling or disease, decreased reproductive success or immature survival arising from flooding of low-lying nests during sea storms,
and losses of eggs, chicks, and fledglings to natural predators.

Introduction:
Crowned Cormorants (Microcarbo coronatus) are endemic to the Benguela upwelling ecosystem off southwest Africa, where they have
bred at 72 sites, 23 in Namibia and 49 in South Africa. These are situated between Bird Rock Platform near Walvis Bay in central Namibia
and No. 12 Stacks in the Tsistikamma section of South Africa’s Garden Route National Park, which is on South Africa’s south coast (Figure
1). In 1982, the species’ breeding distribution was from Bird Rock Platform to 2 km west of Aasfontein, which is west of Cape Agulhas,
the southern tip of Africa (Crawford et al. 1982). Subsequently, four active nests were found at No. 12 Stacks in 2003, which extended
the breeding range of the species by c. 355 km to the east (Whittington 2004). However, on 18 visits to No. 12 Stacks between 2006 and
2019, Crowned Cormorants were not again observed there (Randall et al. 2024), so that range extension was temporary. The only other
site east of Cape Agulhas where Crowned Cormorants are known to have bred is Waenhuiskrans: eight to 31 pairs were nesting there on
three visits made from 2012–2015. This colony is assumed to be still extant and forms the present eastern limit of breeding by the species.
In 2022, Crowned Cormorants were classified in terms of criteria of the International Union for Conservation of Nature (IUCN 2022) as
Least Concern (BirdLife International 2022). However, in 2015 they were considered Near Threatened in both Namibia (Kemper 2015)
and South Africa (Cook 2015).
This chapter updates estimates of numbers of Crowned Cormorants breeding at different sites in southern Africa and describes trends in
those numbers. It undertakes a preliminary assessment of the Red List status of, identifies important breeding areas for, and summarises
threats to the species.

Numbers, trends, and conservation status

Numbers of Crowned Cormorants that bred in different
years at sites in Namibia and South Africa from 1923–
2022 are shown in Table 1. Information was collated
from Crawford et al. (1982, 2012, 2018), Williams (1987),
Bartlett et al. (2003), Whittington (2004), Kemper et al.
(2007), Kemper (2015) and relevant breeding site chapters
in this volume. When multiple counts were obtained at a
site in a given year, the maximum was used. ‘√’ signifies
that breeding occurred at a site but the numbers were not
ascertained; ‘?’ that breeding may have taken place.
The maximum number of Crowned Cormorants varied
between sites from one pair at Geyser Island to 475 pairs at Crowned Cormorants may build substantial nests
Ichaboe Island. Dassen and Robben islands had maxima
of 441 and 405 pairs, respectively; 16 other sites at some al. 1994, Kemper 2015) and, if they did so within periods
stage held > 100 pairs (Table 1). when maxima were summed, there may have been
It was estimated that 2,665 pairs of Crowned Cormorant overestimation.The sum of the most recent counts from
bred from 1977–1981; 977 at 15 sites in Namibia and 1,688 all breeding sites was 2,195 pairs (910 in Namibia and
pairs at 22 sites in South Africa (Crawford et al. 1982). It 1,285 in South Africa, Table 2). This is lower than the
was thought that 2,345 pairs bred from 1995–2006; 1,018 2,657 pairs that bred from 2018–2022, which can be
in Namibia and 1,327 in South Africa (Kemper et al. 2007). attributed to a decrease of 527 pairs at Seal Island,
The overall number of Crowned Cormorants breeding from Lüderitz, between 2000 and 2022. Counts made in the
2013–2017 was 2,748 pairs and from 2018–2022 it was 1990s, 2000s, and 2010/20s contributed 2%, 15%, and
2,657 pairs (Table 2). These totals will be influenced by 83% of the sum of most recent counts at sites, respectively
the extents of surveys in different periods, with incomplete (Table 2).
coverage underestimating numbers. Conversely, Crowned In Namibia, there were 774 pairs from 2013–2017 and
Cormorants often change their breeding sites (Crawford et 1,167 pairs from 2018–2022 (Table 2). In South Africa, 1,688

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