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The main part of Portsdown Hill can be seen from miles around and is a wildlife haven for all sorts of flora and fauna. 

Portsdown Hill


The Small Blue is Britain's smallest butterfly, and there are good numbers on Portsdown Hill where their caterpillars feed on Kidney Vetch which grows all over the downland.


The Marbled White is very common on the downland in June,July and early August, its caterpillars feed on the vast amount of grasses found on the downland.


Bee Orchids can be found dotted all over the downland , along with a host of other wildflowers like Cowslip, Kidney Vetch, Horseshoe Vetch, Birds Foot Trefoil and Common Dog Violet. 

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The Paulsgrove Chalk Pit where Kestrels and Falcons have been seen

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  • Imposing chalk downland escarpment overlooking Portsmouth and the Solent.

  • A central part of the escarpment designated SSSI for its variety of flora and fauna.

  • Wildlife haven on the doorstep of a major city.

  • Chalk downland butterflies include Chalkhill Blue and Small Blue.

  • Green Hairstreak and Brown Argus also present.

  • Fascinating military history including series of defensive forts built during the nineteenth century and second world war tunnels.


Portsdown Hill is a chalk downland escarpment stretching for several miles and overlooking Portsmouth, the Solent and the Isle of Wight. Its strategic position has resulted in the hill playing a significant role in Britain's military history over several centuries - a series of military forts (the Palmerston Forts) built during Napoleonic times being very obvious evidence of that. Despite its proximity to a large city, conservation management and scrub clearance efforts on Portsdown Hill in recent years have substantially improved the quality of its chalk downland, to the benefit of the wildlife, including butterflies. Even the flower-rich ramparts of several of the military forts now provide good butterfly habitat.


The area of the hill located between the disused Paulsgrove and Wymering chalk quarries is probably the richest area for butterflies and is the main breeding site for Chalkhill Blue. Access to the area is through a gate close to Lime Grove and just to the east of the largest of the disused quarries (Paulsgrove), which leads to a network of paths on the hillside. In May, spring species include Orange Tip, Brimstone, Red Admiral and Peacock.  Green Hairstreak can also be found in small numbers around the margins of bushy areas on the lower slopes. Late July/August is the best time for Chalkhills, but Common Blue, Marbled White, Meadow Brown and Gatekeeper should also be seen in this area. Other species to keep watch for include Brown Argus, Small Copper, Small Blue and Clouded Yellow.


Small Blue (especially the main spring brood) can usually be found amongst the scrub on the south side of the imposing chalk face of the Paulsgrove quarry. In particular, follow the chalky path at the bottom of the slope heading west, below the western end of the quarry Look out for Green Hairstreak amongst the gorse in this area too. Visits here can sometimes be accompanied by the raucous screeches of a pair of Peregrine Falcons which have been nesting high on the quarry face for several years.

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Where the Chalkhill Blue flies the areas are kept short for the caterpillar to feed on its food plants of Horseshoe Vetch by Horses and Cattle.

The flower rich meadows have been created through good management and using livestock to keep the ground sward at the right height for species like Chalkhill Blue

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The area is home to a colony of Small Blue

Since the hill provides such a good vantage point, it is not difficult to maintain one's bearings. You can gradually make your way east along the hill towards the other quarry at Wymering. The return can be made by retracing steps or introducing a variation using the network of paths.


I used to record butterflies and moths on Portsdown Hill many years ago (called a transect) and the highlight of any walk was to see the Wall Brown Butterfly. Sadly its vanished from the area, why? we dont really know, suffice to say it's probably down to global warming and pollution. Its hoped that it will return one day.

One of the Palmerston follies known as Fort Widley, behind here was a good area for butterflies including the Wall Brown, and now the Brown Hairstreak has been seen not too far from here. So there is hope that other butterflies may well find a sanctuary here like the Adonis Blue and maybe Silver-Spotted Skipper.


Skylarks can be seen flying over the top of the downland and in the fields on top of the downland. There are many other birds of note, Yellowhammers, Stonechats, Redpolls, and Linnets can also be seen in the summer months.

A Kestrel hovering over the chalkpit where they nest, other birds of prey of note are Buzzards, Red Kites, and the Peregrine Falcon. In 2021 I also saw a White-tailed Sea Eagle over the chalkpit being mobbed by Crows.

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