Grafham Water was created in 1962, when construction of the dam began, but the reservoir was not filled to its current level until 1966.
The reservoir has about 9 miles of shoreline, with most of it is viewable from the cycle-path that encircles it.
Its influence on birding in Cambridgeshire has been impressive. One of the premier sites in the county, it produces an array of rare and scarce birds, as well as nationally important numbers of some wildfowl species. This has afforded it SSSI status.
Located just west of the A1 between Huntingdon and St. Neots, and is best accessed via the B661 at Buckden. There are four main car parks around the reservoir, but by far the most useful is Mander (TL143672), located just west of Perry village. Here you can find the Wildlife Trust offices, adjoining nature reserve, fishing lodge, a café (open 7 days a week), toilets (including disabled) and an outdoor clothing/fishing tackle shop. From here it is possible to walk around the nature reserve trails. The scrub around the trails has a small population of Nightingales, and is good for common warblers in summer, with occasional Firecrest records during passage. From the trail it’s possible to access five bird hides, including Dudney hide (TL137677), which overlooks the main area of the nature reserve and the recently installed tern raft. The creek is excellent for winter wildfowl, with occasional Mandarin, Goosander, Smew, wild Swans, 3 scarce grebes, and an array of waders during passage periods (depending on the water level). The County record count of Ruddy Ducks (121) was recorded here in 2002. Rare birds recorded here have included Great White Egret, Ring-necked Duck and Pectoral Sandpipers, and Britain's third inland Surf Scoter frequented this creek. Bittern has been seen here, with Little Egrets now regular.
This trail is also leads to Littless Wood, a large area of ancient woodland, with a mixture of scrub, conifers and bordering arable land. All common woodland birds breed here, including Marsh Tit and Nuthatch and the area has recorded singing Golden Oriole, Long-eared Owl, Wood Warbler and occasional passage Common Redstarts.
Just east of Perry are the Lagoons. Access is restricted, due to work by Anglian Water. The area has potential for waders, but the sandy filter beds rarely attract more than the common species. In previous year’s rare waders have included Least, Buff-breasted &, Marsh Sandpipers, Black-winged Stilt and Wilson’s Phalarope, as well as Spoonbills, Green-winged Teal, Ring-necked Duck and occasional Scaup. The area holds breeding Water Rail, Cetti’s and Grasshopper Warblers. Jack Snipe are probably regular in winter (but there is NO access down to the pools) where Spotted Crake has been recorded several times and Bitterns are occasional in winter. The areas of scrub around the lagoons are excellent for passage migrants with records of Bluethroat, Red-backed Shrike, Great Grey Shrike, Wood Warbler, Firecrest and Ring-necked Parakeet. Bearded Tit and Water Pipit were once annual, but are now very rare. The northern edge of the lagoons gives a good view over the centre of the reservoir. The east end of the reservoir is accessed from either Plummer car park (TL163666) or Marlow car park (TL167681). Gaynes creek (off Plummer car park) can hold good numbers of wildfowl and occasional waders and scarce grebes. It is possible to follow the cycle path east round the reservoir, and along the top of the dam to obtain extensive views. The Dam is a good place to find waders, with regular sightings of Dunlin, Common Sandpipers and annual Sanderlings, Turnstones and Little Stints. Rarities have included White-rumped Sandpiper and several
Purple Sandpipers (11 site records – holding the county monopoly). Both Red-necked and Grey Phalaropes have been found here several times. It is also the most reliable site in Cambridgeshire for Rock Pipits, with Snow Buntings, Twite and Lapland Buntings all recorded previously. Wryneck, Hawfinch, Red-rumped Swallow, Ring Ouzels, Pied Flycatchers, Redstarts, Whinchats and Black Redstarts have been present around Marlow car park, and the deep water off here is excellent for diving birds, with sometimes hundreds of Great Crested Grebes together, small groups of Scoters (usually Common), scarce grebes, all 3 divers (Great Northern being annual), and occasional Long-tailed Ducks and Red-breasted Mergansers. The north shore is best accessed using Hill Farm car park (TL148694); this is located at the end of minor road running west from Grafham village. From here it is around a mile walk west to the hide at Savages Creek (TL135690). The creek holds large numbers of common wildfowl and is a good area for Smew. Unfortunately, due to its south facing orientation, the viewing is best early or late in the day. The extensive woodland along north shore is good for common birds, with resident Red Kites, Nightingales and Lesser Spotted Woodpecker occasionally.
The main reservoir itself can be viewed from any of the above areas, although Mander car park and the Dam are the best places to search from. The reservoir has a good track record for inland seabirds, including Sooty Shearwater (2013), Leach's Petrel (recorded on a number of occasions now), Storm Petrel (2000 & 2008), Pomarine Skua (1976, 1985, 1987, 1991 & 2007), Long-tailed Skua and Gannet (multiple records) and Little Auk (1988). The site also attracts occasional Manx Shearwaters, Arctic & Great Skuas, Fulmar and Brent Geese. The reservoir is also a great place to see inland Common Scoters.
Common Terns are present in small numbers in passage periods and over 200 Arctic Terns have been recorded together, but smaller numbers are more usual (usually during North-westerly winds). Both Little and Sandwich Terns are almost annual, and Black Terns are present during passage periods (with up to 400 recorded in record years). Rare terns have included Roseate, Caspian, Whiskered and White-winged Black Tern.
In mid-winter it is likely that 50,000+ gulls roost here; viewing usually best from Mander car park, the Lagoons, or Plummer car park, but they can be distant. Increased coverage has recently uncovered regular Mediterranean, Caspian, Iceland and Glaucous Gulls. Little Gulls and Yellow-legged Gulls occur throughout the year. Sabine's Gulls have been recorded rarely, with up to 10 occurring during the 1987 Hurricane. Grafham Water also lays claim to the first Ring-billed Gull in Cambridgeshire and the first and second Laughing Gulls! We eagerly await our first Franklin’s…
Raptors are not well represented around the reservoir, but Ospreys are annual, with some lingering and Hobbies are regular throughout the summer. Rough-legged & Honey Buzzards and Montagu’s Harriers have been recorded on just a few occasions. Marsh Harriers are now annual, but Hen Harriers remain rare passage migrants.
Other rare birds recorded at Grafham include Blue-winged Teal, Corncrake, Stone Curlew, Kentish Plover, Shorelark and Richard’s Pipit, but the site can produce the unexpected;
Strangely, Red-headed Bunting and Marbled Duck were both recorded within a month of each other in 1976!
Mark Hawkes, April 2018