Page 524 - Atlas Sea Birds Ver1

Table 2: Estimates of numbers (pairs) of Grey-headed Gulls breeding coastally in Namibia and South Africa from Brooke et al. (1999), for 2018–2022 and
for five decadal periods (1970s, 1980s, 1990s, 2000s, 2010s) based on maximum counts at colonies observed in those periods. Also shown is the most
recent value for each site, the year of that observation and its percentage contribution to the total of the most recent values. The decade of observations
is colour-coded and the percentage contribution of values from different decades to the sum of the most recent values is indicated. Sub-sites of Swartkops
River valley and Lake St Lucia are shown in red. Those sites that contributed ≥ 1% of the sum of most recent counts are highlighted with grey shading. ‘√’
signifies that breeding occurred at a site but the numbers were not ascertained. Note the Algoa Bay entry sums all breeding records in that bay.
≥ 1% % of sum of most recent estimates from
Maximum pairs of sum different decades
observed/estimated of most
Most
Site recent Year of % of sum recent 1980s 1990s 2000s 2010s/20s
of most
most
Brooke This estimates 2.10 0.00 4.70 93.19
et al. study estimate recent recent
(1999) 2018- (pairs) estimate estimates Maximum pairs observed/estimated per decade
up to 2022 1970s 1980s 1990s 2000s 2010s
1999
Namibia
Cunene River Mouth 6 2002 0.60 6
Swakopmund 2 0 0 2021 0.00 2
Saltworks
Swakopmund Sewage 1 1 1982 0.10 1
Works
Walvis Bay Bird 500 20 1984 2.00 500 20
Paradise
Shark Island, Lüderitz 2 0 0 2021 0.00 2
South Africa
Bird Island, Lambert's
Bay 1 0 0 2019 0.00 1 0
Wadrif Soutpan 6 6 2018 0.60 6
Malgas Island 1 0 0 2019 0.00 1 1
Marcus Island 2 0 0 2019 0.00 2 0
Jutten Island 2 0 0 2019 0.00 2 0
Schaapen Island 1 0 0 2019 0.00 1 0
Paarl Sewage Works 25 20 2017 2.00 25 20
Robben Island 3 4 4 2019 0.40 3 3 8
Rietvlei 11 0 0 2019 0.00 11 0
Caltex Oil Refinery 2 0 0 2019 0.00 2 0
Century City 0 0 2019 0.00 3 0
Athlone Sewerage 3 0 0 2019 0.00 3 0
Works
Cape Town waterfront 0 0 2019 0.00 3 1
Strandfontein 3 0 0 2019 0.00 0
Sewerage Works
Theewaterskloof Dam 40 2004 4.00 40
Dyer Island 4 1 1 2019 0.10 1 4 2 1
SoetendalsVlei 1 0 0 2018 0.00 0
Near Bredasdorp 2 0 0 2018 0.00 0
De Hoop Vlei 23 0 0 2018 0.00 0
Algoa Bay 95 836 836 2022 83.68 133 120 608 248
Swartkops River valley 95 834 834 2022 133 120 608 234
Bar None Saltpans 0 2022 0 120 608 234
Chatty Saltpans 95 824 2022 64 82 153 31
Redhouse Saltpans 28 10 2022 69 0 0 0
Power Station pans 0 2022 95
Fishwater Flats 0 2022
Tippers Creek 8 2016
Coega River Saltworks 31 0 456 2008 456 75
Sundays River 2 2 2022 0.20 31 3
Saltworks
Lake St Lucia 750 64 64 2021 6.41 750 500 1500 728 400
Vincent Islands 2 1970 2 1500 400
Lake Bhangazi South √ 2009
Lane Island 400 2013 750 500 728
Lane Island extension √ 2012 1500
Bird Island 100 2001 100
North Island √ 1967 94
Selley's Lakes 68 2003 95
False Bay north 64 64 2021
Muzi Pan 1 2004 0.10 1
Total Namibia 505 0 27 2.70 504 21 0 6 0
Total South Africa 929 911 972 97.30 756 636 1670 1385 685
Total overall 1434 911 999 100.00 1260 657 1670 1391 685

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