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Piscivores Table 3. Water-associated birds recorded at Uilkraals Estuary (Summers et al. 1976; Heydorn & Bickerton 1982; A. Terörde, unpubl. data). Invertebrate feeders African Darter Anhinga rufa African Oystercatcher Haematopus moquini African Fish-eagle Haliaeetus vocifer African Sacred Ibis Threskiornis aethiopicus African Spoonbill Platalea alba Bar-tailed Godwit Limosa lapponica Black Stork Ciconia nigra Blacksmith Lapwing Vanellus armatus Cape Gannet Morus capensis Blackwinged Stilt Himantopus himantopus Cape Cormorant Phalacrocorax capensis Cape Wagtail Motacilla capensis Caspian Tern Sterna caspia Common Greenshank Tringa nebularia Common Tern Sterna hirundo Common Ringed Plover Charadrius hiaticula Crowned Cormorant Phalacrocorax coronatus Common Sandpiper Actitis hypoleucos Giant Kingfisher Megaceryle maxima Eurasian Curlew Numenius arquata Great Egret Casmerodius albus Curlew Sandpiper Calidris ferruginea Greyheaded Gull Larus cirrocephalus Grey Plover Pluvialis squatarola Grey Heron Ardea cinerea Kittlitz's Plover Charadrius pecuarius Hartlaub's Gull Larus hartlaubii Little Stint Calidris minuta Kelp Gull Larus dominicanus Marsh Sandpiper Tringa stagnatilis Little Egret Egretta garzetta Ruddy Turnstone Arenaria interpres Malachite Kingfisher Alcedo cristata Sanderling Calidris alba Osprey Pandion haliaetus Terek Sandpiper Xenus cinereus Pied Kingfisher Ceryle rudis Three-banded Plover Charadrius tricollaris Reed Cormorant Phalacrocorax africanis Whimbrel Numenius phaeopus Sandwich Tern Sterna sandvicensis White-fronted Plover Charadrius marginatus Swift Tern Sterna bergii Herbivores White-breasted Cormorant Phalacrocorax lucidus Common Moorhen Gallinula chloropus Egyptian Goose Red-knobbed Coot Yellow-billed Duck Alopochen aegyptiaca Fulica cristata Anas undulata Table 4. Summary of bird count results conducted at the Uilkraals Estuary. January 1976 (Summers et al. 1976) January 1976 (Summers unpublished data) December 1979 (Heydorn & Bickerton 1982) January 1981 (Ryan et al. 1988) February 1996 (Barnes 1996) February 2010 (A. Terörde, unpub. data) Number of species Total abundance Wader abundance Most abundant species 32 Not counted 774 Waders: Curlew Sandpiper (480) 17 4864 720 Sandwich Tern (2000) Waders: Curlew Sandpipers (440) 26 5879 584 Sandwich Tern (5000) Waders: Curlew Sandpiper (480) 24 6755 880 Common Tern (4720) Waders: Curlew Sandpiper (534) 30 2180 1041 Common Tern (513) Waders: Curlew Sandpiper (421) 22 435 60 Kelp Gull (310) Waders: Whimbrel (17) Uilkraals Estuary Situation Assessment 29 Anchor Environmental
For this study, a count of water-associated birds was conducted in late February 2010, when summer migrant numbers are usually maximal. Birds were recorded from the mouth to the section of the estuary where the wider channel becomes a series of smaller braided channels, approximately 3 km from the mouth. Counts during this study showed a drastic decrease in bird numbers compared to previous years, while diversity was not affected as much (Table 4). Only 435 individuals were recorded, the majority of these being Kelp Gulls (310 individuals). Most birds (89%) were found in the sandflats above the bridge (Error! Reference source not found.). Ten species were piscivores nd 12 species were invertebrate-feeding waders. No herbivores were recorded. Compared to the study by Barnes (1996) the proportion of invertebrate-feeders, piscivores and herbivores was similar. Barnes (1996) recorded 15 species of piscivores, 18 species of invertebratefeeders and one species of herbivore (Egyptian Goose). The low numbers can be explained by the significant decrease in the numbers of Curlew Sandpipers, as well as only a small number of terns being present (32 individuals) as compared to previous counts (Error! Reference source not found.). Curlew Sandpiper has been recorded t the estuary in high numbers during every previous survey conducted (Error! Reference source not found.). It is an Arctic-breeding migratory species, and is found in southern Africa from August/November to March/April. It forages for nereid worms, snails and crustaceans mainly in the intertidal area of coastal lagoons and estuaries and on sheltered open shores with much stranded algae (Hockey et al. 2005). The estuary was closed to the sea during the study and had been closed for approximately two months. Therefore, the large inter-tidal feeding habitat which covered the entire sandflat region below and above the road bridge was lost. Most inter-tidal invertebrates had probably desiccated and died or migrated elsewhere. While many sandprawn burrows were still present, these animals are able to burrow deeper to a level of sufficient moisture in dry times and are often found in closed systems. They are also very tolerant of varying salinities (Forbes 1974). Due to their large size and the depth of their burrows it is unlikely that sandprawns can be utilised as prey by small invertebrate-feeding waders. Kelp Gulls were recorded roosting for the first time in high numbers at Uilkraals with 310 individuals recorded (Table 5). Barnes (1996) recorded 67 and Ryan et al. (1988) recorded 77 individuals. On the day of the count a strong south-easterly wind was blowing and it is possible that this species seeks shelter in the estuary sporadically. Similar numbers of Kelp Gulls were, however, still present the following two days, even after the wind had died down. The low numbers of terns recorded are of particular concern as this site was once a major roost for several tern species including the Caspian Tern, Sandwich Tern and Swift Tern, of which it hosted 6.8%, 2.8% and 6.6% respectively of the south-western Cape’s population (Barnes 1996). Whimbrel has previously been recorded in high numbers at the estuary (76 and 65 individuals) making it the second largest population in the south-western Cape after Langebaan Lagoon (Barnes 1996). Only 17 individuals were recorded in this study. Whimbrel are relatively sensitive to disturbance and higher levels of recreational use of the estuary by people may be a contributing factor, in addition to the loss of intertidal feeding habitat. Uilkraals Estuary Situation Assessment 30 Anchor Environmental
Page 1 and 2: C.A.P.E. Estuaries Management Progr
Page 3 and 4: ubble spanning almost two-thirds of
Page 5 and 6: estuary’s functioning is catered
Page 7 and 8: ABBREVIATIONS AND ACRONYMS WMA BAS
Page 9 and 10: The reserve determination process .
Page 11 and 12: construction of the Kraaibosch dam
Page 13 and 14: The Uilkraals catchment lies within
Page 15 and 16: The Kraaibosch dam (Figure 6) was c
Page 17 and 18: eaches and tourism and fishing indu
Page 19 and 20: 3. ECOLOGICAL CHARACTERISTICS AND F
Page 21 and 22: The first time in recorded history
Page 23 and 24: 3.2 Water chemistry The distributio
Page 25 and 26: other associated high water levels.
Page 27 and 28: 3.6 Fish Estuaries provide an extre
Page 29: Table 2. Species composition, abund
Page 33 and 34: score of 55 (van Niekerk, unpubl. d
Page 35 and 36: 4. ECOSYSTEM SERVICES 4.1 What are
Page 37 and 38: isolation, but only inasmuch as it
Page 39 and 40: 4.8 Genetic resources Genetic resou
Page 41 and 42: 5. LEGISLATION AND MANAGEMENT ISSUE
Page 43 and 44: Land use & management Water quality
Page 45 and 46: Table 10. Provincial and local gove
Page 47 and 48: Goal # Goal Strategies practices do
Page 49 and 50: 5.4 Exploitation of living marine r
Page 51 and 52: In terms of ICMA, all land within o
Page 53 and 54: (e) stabilising walls; (f) building
Page 55 and 56: Table 14 (Overstrand Local Municipa
Page 57 and 58: Table 13. Overberg District Spatial
Page 59 and 60: Component Strategy with spatial imp
Page 61 and 62: Component Strategy with spatial imp
Page 63 and 64: Table 14. Overstrand Local Municipa
Page 65 and 66: Component Description Policies 9. S
Page 67 and 68: Issues of surrounding land use and
Page 69 and 70: protected area by a single manageme
Page 71 and 72: 6. REFERENCES Adams, J.B., Bate, G.
Page 73 and 74: Smith, N & Cullinan, C. 2000. Revie
Page 75 and 76: 8. Plan for awareness-raising and p

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