Regular visitor at all times of the year, but mainly in winter and spring, that has bred.

Great Crested Grebes are regular visitors to Fairlands Valley Lakes, having first being seen there on 9 April 1974. There are records for every month of the year. When five were seen on 12 March 1975 it was at that time the largest number recorded in North Hertfordshire. Nine have since been seen on 29 April 2016 and 6 November 2023.

Breeding, and attempted breeding has also occurred at Fairlands Valley Lakes; 1983 (one pair raised one young), 1984 (one pair raised four young, three of which died later), 1990 (one seen, “on eggs” on 21 April), 1992 (one pair, two/three young), 1993 (three broods, five juveniles), breeding recorded between 1994 and 1997, 1998 (attempted pairing and nest building), 2003 (a pair seen displaying between 3 and 15 April),  2004 (one pair bred), 2008 (a pair displaying on 20 April), 2010 (a pair displaying on 22 April), 2015 (three pairs displaying during March and April), 2016 (one brood and a juvenile seen on 12 August), 2019 (bird seen on a nest during August), 2020 (nest with eggs destroyed during June), 2021 (three failed breeding attempts), 2022 (failed breeding attempt).

Whilst juvenile birds have been seen in the breeding seasons of, 2002 (23 and 25 May) and, 2008 (13 June), there are no records of breeding for those years.