Stockbridge Marsh & Down

Jointly with the Alton Natural History Society

We first stopped at the northern hedgerow, where a range of butterflies were identified: the Comma with its distinct white C-shaped mark on the underside of the hind wing; the Gatekeeper, which has a single ocellus or eye-spot and which is a defence against bird attack; the Meadow Brown, the Large White, Red Admiral which overwinters in the south and is supplemented by migrants from the continent. The main food source for all these butterflies was the bramble blossom.

The water also provides habitats or food sources for birds. The house martins flew low over the water in their search for insects; it was noted that there has been a significant drop in insect numbers over recent years. A little grebe was sitting on its nest while young moorhens were observed in their search for food. A female mandarin duck was spotted in an inlet off the river; this bird is becoming common on Hampshire's rivers and in the New Forest. The reed warblers were identified by their singing, while there were glimpses of a kestrel and a sparrow hawk in flight. The green woodpecker was recognisable from its distinctive flight, which is described as "…deeply undulating, with long wing-closures between each upward bound."

The damp marginal conditions suit a range of flora, including meadow sweet, purple loose strife, hemp agrimony and tussock sedges. The study of the last of these is a specialised field of expertise. The tussocks can reach as much as 1.3 metres high and 1 metre wide, with stiff 1-1.5 metre stems and long leaves, though the examples shown in this photo are around half that size.

On the right bank of the river water vole holes could be seen and one, but only one, of these could be seen. The river at this point flows through an area of peat and the water is much darker in colour with low visibility.

After lunch we visited Stockbridge Down. This area of chalk downland (SU379349), a mile to the east of Stockbridge, rises to a height of 158 metres in the north with the ground sloping steeply down to the north-west and more gently to the south and east. The National Trust has more actively managed the down in recent years with scrub clearance and the fencing off of some parts. As the picture shows, it is grassland with some bushes and trees on the high ground.

The down has a range of chalk flora. Marjoram was in flower; it is a good food source for a range of butterflies. The blue flowers of the Harebell were in blossom; Lady's Bedstraw, Eyebright, Wild Carrot and Wild Basil were also in evidence. Unfortunately the timing of the season did not allow us to see the Frog Orchid in flower.

The weather was suitable for several species of butterfly and we saw, early Chalkhill Blue, Marbled White, Meadow Brown, Small Heath, Brimstone, Peacock and Gatekeepers. There was discussion of a number of matters related to their lifestyles. The Brimstone feeds up early in the summer to allow it to hibernate to avoid the heat, which can dry it out. The Peacocks were also the result of breeding in the spring and they too were feeding to allow them to hibernate and overwinter. It was suggested that the Small Heath was the commonest butterfly. The Gatekeeper has a habit of flying to a hilltop where numbers of the species meet to fly together.

The Landscape Section would like to express its thanks to the members of the Alton Natural History Society for its expertise on this trip. We look forward to future joint events.