21a79c3c1de95de1a93456d3c9885a13 English dataset Natural England Marine GI Team +44 (0)300 060 3900 +44 (0)300 060 2356 Foss House, Kings Pool, 1-2 Peasholme Green York YO1 7PX enquiries@naturalengland.org.uk pointOfContact 2022-01-31 MEDIN Discovery metadata standard 2.3.8 urn:ogc:def:crs:EPSG::4326 2018 Natural England (NE) Digital video aerial surveys of red-throated diver in the Outer Thames Estuary Special Protection Area 2018-06-28 publication NECR260 http://https://www.gov.uk/natural-england This report provides a new population estimate for the original Outer Thames Estuary SPA for red throated diver of 21,997. The estimated total for the new, enlarged SPA (formerly the pSPA) is 22,280. Both these figures are approximately 3.5 times greater than the notified population of the original SPA (6,466 individuals). This increase in the recorded number of red-throated divers, coupled with the numbers of individuals of other species recorded has resulted in a peak waterbird population estimate across the original SPA of 41,918 and across the newly enlarged SPA of 46,056 individuals. This suggests that on occasion the SPA supports an assemblage of wintering waterbirds well in excess of the size (20,000 individuals) required to consider this to be qualifying feature of the SPA. Red-throated divers appear to use the additional area now included within the larger revised SPA boundary at low densities and at high tide when mudflats are covered. Anthropogenic effects on the distribution of several species were detected, notably strong displacement of red-throated diver was noted from areas within offshore windfarms and from areas of shipping activity. This lead to higher densities of birds at points furthest from anthropogenic activity. Catherine Irwin HiDef Aerial Surveying Limited Lead Project Manager catherine.irwin@hidefsurveying.co.uk originator Natural England Marine GI Team +44 (0)300 060 3900 +44 (0)300 060 2356 Foss House, Kings Pool, 1-2 Peasholme Green York YO1 7PX enquiries@naturalengland.org.uk custodian notPlanned Marine Environmental Data and Information Network Habitats and biotopes GEMET - INSPIRE themes, version 1.0 2008-01-06 revision Habitat extent SeaDataNet P021 parameter discovery vocabulary 2009-11-16 revision OGL otherRestrictions OGL English biota SeaDataNet vertical extent keywords 2010-01-01 revision littoral -0.1122 2.0301 51.3751 52.4660 2018-02-04 2018-02-17 Natural England Marine GI Team +44 (0)300 060 3900 +44 (0)300 060 2356 Foss House, Kings Pool, 1-2 Peasholme Green York YO1 7PX enquiries@naturalengland.org.uk distributor http://publications.naturalengland.org.uk/publication/4813740218515456 A link to the general host site dataset HiDef Aerial Surveying Limited (HiDef) were contracted by Natural England to undertake digital aerial surveys of the Outer Thames Estuary SPA with the core objective being to ascertain numbers of red-throated diver Gavia stellata. Recording of secondary species was to take place but was not deemed the priority of the project. Flights were undertaken on 4 and 17 February 2018, with two Diamond Aviation (DA) 42 Twin Star aircraft flying sorties on each date. Results for these surveys are presented in this report alongside comparisons with previous surveys. When this contract was commissioned (autumn 2017) a decision to extend the existing Outer Thames Estuary SPA to include an additional c.95km² of sea, adjacent to its existing southern boundary off the Essex coast, with a revised pSPA boundary was pending. This was approved during the course of the contract. Therefore, two sets of numbers are presented at key points in the report to describe numbers within the new, extended SPA boundary and within the smaller boundary of the original SPA. The latter allows easier comparisons with previous surveys that covered only the original SPA. The new pSPA enlarges the existing Outer Thames Estuary SPA (classified solely for nonbreeding red-throated divers) to include three new areas identified for foraging terns Sterna sp. breeding at other (already classified) SPAs on shore, these are parts of the Rivers Yare and Bure, a small riverine section at Minsmere, and both estuarine and marine areas around Foulness. The pSPA therefore comprises areas for foraging breeding seabirds and non-breeding waterbirds. The feature of the existing SPA is retained, and new qualifying features are added based on a review of up-to-date bird abundance information. The total area of the Outer Thames Estuary pSPA is approx. 391,910 ha (392km²).