The Natural History of Slapton Ley

Birds

Slapton Ley NNR possesses the largest complex of reedbeds (28 hectares) in Devon.  It has SSSI (Site of Special Scientific Interest) status and is important for its wintering wildfowl, passage migrants (in particular warblers, swallows and Alba wagtails), breeding Great Crested Grebes, Reed Warblers and Cetti's Warbler and over-wintering Bittern. 

Wintering wildfowl are monitored regularly as part of the national monthly WeBS (Wetland Bird Survey) counts and there has been a more intensive study of the Great Crested Grebe, which re-colonised in 1973 after a break of almost 30 years. Breeding was recorded on at least three years in the 1930s, and again in 1945, but rarely of more than one pair. 

Swallows, wagtails and warblers are all studied as part of a regular bird ringing programme.  Migrant warblers have been the main ongoing interest at Slapton since 1961 when ringing first started. During that time birds entering the regular autumn Swallow roost are caught annually.  Between 2002 and 2006 these catches were made as part of the BTO/European Swallow Roost Project and nestlings bred in the southern half of the Slapton catchment were also ringed as part of this project in 2005 and 2006.  An intensive study of Pied/White wagtails (Motacilla alba) including regular counts as well as ringing has been carried out since 2002 and shown the importance of Slapton Ley for migrant birds from Iceland (White - Motacilla alba alba) and upland areas of the UK (Pied - M.a.yarrellii) with winter influxes as birds also move out of lowland Britain in the face of severe weather.   The reedbeds are important for breeding Reed Warblers and the whole site is important for breeding Cetti's Warbler which first colonised in 1976 and reached a maximum number of 60 territorial males in 1996.  Slapton is the third most important site in the UK for breeding Cetti's Warbler, and the scrub surrounding the Ley and adjacent areas holds a number of breeding Sedge Warblers.

Bittern, probably of continental origins, regularly overwinter and a pair bred in 1996 and 1997. Marsh Harriers pass through on passage, and a semi-resident female has been present since 2001.

For more detailed information about the birds that can be found at Slapton Ley, and the ringing operation that goes on, please click on the menu tabs on the right.