Photo 1 - Steep Downland Slope North-East Of The Hill Fort 

Highlights

National Nature Reserve on chalk downland owned and managed by English Nature

Site crowned by iron age hill fort providing fine views

One of the best sites in the country for Chalkhill Blue

Good colonies of Dark Green Fritillary and Silver-spotted Skipper

Grizzled Skipper, Dingy Skipper and Green Hairstreak present in small numbers

Possibility also to see Adonis Blue, although becoming very scarce

Description

Old Winchester Hill is a National Nature Reserve on the South Downs just east of the village of Warnford in the Meon valley. It is also the site of an Iron Age hill fort with many prehistoric features still visible, such as earthworks, barrows and tumuli. The flat topped summit of the fort itself, complete with triangulation pillar provides fine views, especially south towards Portsmouth and the Isle of Wight.

This large nature reserve, owned and managed by English Nature, is noted especially for its flora, which includes at least 6 species of orchid, and of course for its butterflies. The butterflies thrive on the species rich grassland, whose low nutrient value acts as a natural barrier to vigorous encroachment by scrub. The diversity of species is further enhanced by the habitat variations resulting from the natural topography of the site and its prehistoric man made features.

Old Winchester Hill is one of the most prolific sites in the UK for Chalkhill Blue - with numbers reaching many hundreds across the reserve in good seasons! It is also a good site for Dark Green Fritillary, Silver-spotted Skipper and common species. The site was also selected by English Nature in the early 2000s to re-introduce Adonis Blue. After early success, Adonis numbers have declined  are now precariuously low following a series of wet summers.

Photo 2 - View South From the Fort Area

For this feature, it is convenient to use two widely separated locations which are both good for butterflies, since other areas of the reserve can be readily accessed from one or other of them.  I will assume access is from the main car park (arrowed on this map), however for the fort area there is also limited road parking close to pedestrian entrances further south along the minor road.

The first location is at the bottom of the car park slope. Hence, from the car park, enter the reserve through the gate and turn almost immediately right, passing in front of a gazebo shaped structure containing visitor information (take a look!). Continue through another gate and head straight down the grassy slope. Depending on time of year, species which can be found on this heavily rabbit grazed area of the slope include Chalkhill Blue, Meadow Brown, Small Heath and a few Silver-spotted Skippers. Towards the bottom of the slope, just before the path takes a left turn, pause and look around.  The area of more varied vegetation to your left (arrowed on this map)  and in front of you, including a small meadow at the bottom of the slope across a partially 'flattened' wire fence, is a good place to look for several key species, depending on timing. In this area I have seen  (in small numbers) Green Hairstreak, Grizzled Skipper, Dingy Skipper and Adonis Blue. Chalkhill Blue can present in significant numbers and Silver-spotted Skipper not too difficult to find. Clouded Yellow are also not an unusual sight in this area. Common species such as Common Blue and Small Heath can also be found here.

If you continue along the path as it turns left, you reach an area of steep open downland (Photo 1 at top of page). Look here for fast flying Dark Green Fritillaries during July. However this very active species rarely seems to settle for long on this site and can be difficult to photograph. In addition, departing from the paths is discouraged, bearing in mind the site was used in World War II for mortar testing. One can continue onwards through the section of woodland to another area of downland and then uphill (keeping to the paths!) to the fort area which is close to the second location I have selected. However, I will describe the route to the fort as if making a separate visit, starting from the car park.

In this case, after entering the reserve from the car park, just continue along the main path. The fort is just over 1km from the car park, the path heading south parallel to road for about half that distance before turning right towards the fort. In the first section, Marbled White can be very numerous amongst the long grasses, as well as Small/Essex Skippers, Meadow Brown and Chalkhill Blue (which at peak season can be found in almost all grassland areas of the reserve). In July look over the fence on the right and watch for fast flying Dark Green Fritillary on the steep slope.

After the path takes a right turn, there are usually fewer butterflies to be seen along the section approaching the fort, except for some common Nymphalid species such as Red Admiral and also Chalkhill Blue, depending on time of visit. Now go through the gate marking the entrance to the fort area itself. Some areas of the fort (especially parts of the ramparts which surround the fort) may be roped off to protect nesting birds, but butterflies are normally plentiful even along the rampart edges (Chalkhill Blue, Small Heath, Small/Essex Skipper, Meadow Brown, Painted Lady and even the occasional Clouded Yellow) and a full circuit around the fort is worthwhile if time permits, perhaps with a foray to its flat summit where there is a triangulation pillar.

Photo 3 - Original Re-introduction Site for Adonis Blue

The original Adonis Blue re-introduction site (Photo 3) is on a sloping meadow running south from the fort with bushes and scub on its lower slopes. It is accessed via the gate shown in photo 2. Sadly, Adonis Blue are now scarce here, however this location is good for other species. The lower slopes and scrub areas normally have the most butterflies - here there is shelter and a greater nectar supply. Chalkhill Blue can be abundant here, but other key species which can be found include Green Hairstreak (bushy areas and scrub), Sliver-spotted Skipper and if you are lucky, Adonis Blue. Common Blue are also found in the scrub areas as well as the occasional Brown Argus.