Uncommon resident and winter visitor.

Song Thrushes are a species in decline, both locally and nationally, with their numbers reduced by around 73%. This decline has been taking place since 1940, and is probably linked to land use changes, removal of hedgerows, climatic changes, and the increased use of pesticides.

The 1973 and 1992 Breeding Atlases confirmed breeding from all 11 of the tetrads covering Stevenage, the 2012 Atlas from seven.

Song Thrushes like other Thrush species are particularly affected by hard winters. They suffered heavy mortality in Hertfordshire during the 1878/79 winter, large losses also occurred following the winters of 1880/81 and 1890/91. In the twentieth century the winter of 1947/48 took the population to a very low level and their numbers dropped by 41% after the 1962/63 winter.

The 2012 Winter Atlas confirmed their presence from all 11 of the tetrads covering Stevenage.

As well as the effects of winter weather it has also been discovered that following the hot summer of 1976 they are also vulnerable during hot summers. In summer snails form a major part of the Song Thrush diet and they are more dependent on this food source than at other times of the year. This is also the time of year when greater use of molluscicides are made in gardens to control snails and slugs, reducing this food source and subsequently the survival rate of both juvenile and adult birds.

On 20 January 1989 there was an apparent, “fall” of Song Thrushes in Hertfordshire, with 80 to 100 being seen in the Stevenage area.

At Watery Grove between 1972 and 1989 the Common Bird Census recorded them holding breeding territories annually, with the exception of 1986. The most territories held was 12 in 1981. From 1990 until 1999, although their presence was recorded in those breeding seasons, only single territories were held in 1993 and 1997.