An extensive complex of former and active gravel pits close to the A1, northwest of St Neots. Scrub and woodland surround the more mature Pits, with large numbers of warblers in spring and summer and the highest population of Nightingales in Cambridgeshire (25 singing males in 2000). More than 60 breeding species, including Kingfishers, Grey Herons, Little Grebes and one of the largest inland Cormorant colonies in the UK (c. 100 nests). The shingle islands on two of the lakes make Paxton Pits one of the most important sites in the Ouse Valley for breeding Lapwing, Redshank, Ringed Plover and Common Tern (with Oystercatcher breeding occasionally).

Spring and autumn can be good for passage migrants, with Avocet and Black-tailed Godwits annual in recent years. In winter, the Pits play host to large numbers of ducks, especially Pochard and Tufted Duck; Smew, Black-necked Grebe and Goosander are annual. A Bittern has wintered here for several winters during the late 1990s. Rarities have included Killdeer, Caspian Tern and Red Footed Falcon.

Access from car park at north end of Little Paxton village (signposted from Great North Road). Grid ref: TL 195 629. The visitor Centre opens most weekends. Trails and footpaths provide access to much of the area (see board in car park), while two hides overlook the Heronry Lake. Access to working areas is strictly forbidden. For more information about the reserve, events and recent sightings, visit www.paxton-pits.org.uk A checklist of the 217 species recorded at the Pits and an annual report on breeding birds at the site are available from the Visitor Centre.