North Thames Estuary and Marshes Breeding Bird Survey.

Published online
06 Sep 2023
Published by
Natural England
Content type

Gilmore, G.

Publication language
England & UK


A breeding bird survey was commissioned by Natural England to investigate the breeding bird interest in land adjacent to the Mucking Flats and Marshes Site of Special Scientific Interest (SSSI). The existing SSSI provided a valuable resource for over wintering ducks and waders. Mucking Flats and Marsh Marshes form the largest intertidal feeding area for wintering wildfowl and waders, west of Canvey Island on the north bank of the Thames in the UK. The mudflats and saltmarshes are also a valuable staging post for passage migrants. Between April and July 2022, EMEC Ecology conducted a breeding bird survey to determine the distribution and breeding status of target assemblage species, associated with the habitats found within the survey area (lowland scrub, lowland farmland, lowland fen, lowland open water and lowland damp grassland). Seven surveys were conducted by up to three surveyors throughout the aforementioned survey season, comprising early morning visits for diurnal species and evening visits for crepuscular and nocturnal species. The locations of the nesting sites have been redacted to protect them from disturbance. Throughout the survey, a total of 24 confirmed breeders were recorded from the survey, with an additional 16 probable breeders and four possible breeders, listed within the aforementioned habitat assemblages. These included Recurvirostra avosetta, Tyto alba, Buteo buteo, Emberiza calandra, Cuculus canorus, Sterna hirundo, Numenius arquata, Cettia cetti, Egretta garzetta, Mareca strepera, Podiceps cristatus, Locustella naevia, Anser anser, Motacilla cinerea, Sylvia borin, Ardea cinerea, Falco tinnunculus, Vanellus vanellus, Asio otus, Tachybaptus ruficollis, Linaria cannabina, Charadrius dubius, Aegithalos caudatus, Sylvia curruca, Pica pica, Circus aeruginosus, Cygnus olor, Luscinia megarhynchos, Aythya ferina, Motacilla alba, Coturnix coturnix, Emberiza schoeniclus, Tringa totanus, Corvus frugilegus, Charadrius hiaticula, Acrocephalus arundinaceus, Columba oenas, Hirundo rustica, Gallinago gallinago, Tadorna tadorna, Spatula clypeata, Acrocephalus schoenobaenus, Anas crecca, Aythya fuligula, Rallus aquaticus, Emberiza citrinella and Motacilla flava. The survey area also supported populations of Cetti's warbler (Cettia cetti) and pochard (Aythya ferina) exceeding 1% of the UK's populations (66 singing males and 13 pairs, respectively).

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