I had no idea I had such a delightful spot in my kingdom,? exclaimed the Prince Regent following an outing in 1818 to the 500-acre Brownsea Island, the largest of eight islands in Poole Harbour, Dorset, and which today is owned by the National Trust.

Over the centuries, Brownsea has had a remarkably varied and stormy history from Viking raids under King Canute, to the construction of a blockhouse known as Brownsea Castle, intended to fortify the island against foreign invasion, and which later was garrisoned by Parliamentary troops during the Civil War. In more recent years, ownership of the island passed through many hands and in 1927 it was purchased by Mary Bonham-Christie for £125,000. A recluse by nature, she evicted all the island?s residents to the mainland and allowed the island almost to revert to heathland, scrub and natural woodland. It was during her tenure of ownership that, in 1934, a major fire reduced the island to smouldering ashes after burning for a week. Later, to add to its troubles, it was heavily bombed during World War II, when large flares were placed on the western end to lure Luftwaffe bombers away from the port of Poole.

In 1961, aged 98, Bonham-Christie died and the island passed to the Treasury to pay for death duties. The Government then handed it over to the National Trust and work to make it fit for visitors got underway. It was a massive undertaking. Tracks and paths were cleared through overgrown areas and the massive task of clearing acres of rhododendrons which had invaded so much of the island, was set in motion. The castle was renovated and leased to the John Lewis Partnership as a holiday home for staff, while Lady Olave Baden-Powell, the chief guide, opened Brownsea Island to the public at a ceremony on 15 May 1963. It was a fitting reminder that in 1907 her late husband, Robert Baden-Powell, founded the Scout movement on the island, a minor event at the time but which was to have worldwide significance.

Since 1962, a 100-hectare reserve on the north side of the island has been leased by the Dorset Wildlife Trust (DWT) from the National Trust and which, due to its diverse habitat, including large stands of Scots pine, oaks, beech and chestnut, reed-beds, old meadows, two freshwater lakes and an enclosed lagoon, attracts a wide variety of birdlife and invertebrates.

Visitors to the reserve, landing on the island by ferry, walk several hundred yards, passing by the visitor centre and a small church, then turn up a track leading to the headquarters of the DWT, a former vicarage built in 1854, known as The Villa, but which has never housed a vicar (he never turned up!). This is home to Chris Thain, aged 50, the reserve manager who has been on Brownsea for 25 years, first as assistant to his predecessor and then for the past 11 years as manager. The reserve warden, who has been in the post for 10 years, is Abby Gibbs. The Villa has a small shop, wildlife exhibition and workshops and accommodation for staff and volunteers.

Ten nights with terns

One of the main visitor attractions is the enclosed lagoon, its nearest island bank little more than 100 yards from The Villa. A complex of non-tidal brackish water with mudbanks, salt marsh and shallow islands, it attracts a wide variety of waders, duck and gulls. Here, in the spacious MacDonald hide, we were able to watch dozens of sandwich and common terns nesting and feeding young on five artificial sandbanks only a short distance from the enclosed viewing platform.

Last year?s sandwich tern breeding season was a disaster. Only three chicks were raised from a total of 231 terns, the result of predatory visits by herons, mostly at night. This year, however, Chris spent 10 nights sleeping in the hide during the most critical period and managed to scare off the herons, with the result that, as we saw, a substantial number of young terns in varying stages of growth were keeping their parents busy with a sand-eel shuttle.

From my point of view, the two most interesting mammals on Brownsea are the red squirrels, with a population of around 200, and the sika deer. Fortunately, no grey squirrels have invaded the island and the pine woodland provides an ideal habitat for the red squirrels. However, in order to ensure tree regeneration, the tangle of ever spreading rhododendrons has been under attack for the past 50 years and now, after stalwart work from volunteer groups over that period, the last rhododendron is scheduled to be cut at a special ceremony in the autumn.

The red squirrels are elusive but, for the benefit of visitors, they are attracted to bird feeders suspended close to The Villa. Here we were able to watch a brace of squirrels, appearing much smaller and more graceful than their unwanted american cousins, as they swung on the feeders in search of nuts. The population is stable and, together with the Isle of Wight red squirrels, represents the entire red squirrel population in southern England.

Unwelcome guests

There are, Chris told me, currently around 30 sika hinds on the island, many of which are about to calve. However, they are not particularly welcome on Brownsea as their browsing tends to prevent woodland regeneration and the population is augmented by prickets and stags during the autumn rut. These readily swim over from the Purbeck mainland, which sustains a very large population of sika.

The history of these deer, in association with Brownsea, is fascinating. The very fi rst Japanese sika were brought into England in 1860 when a pair were presented to the Zoological Society for its collection at Regent?s Park. In the same year a stag and three hinds were obtained from a London animal dealer by Viscount Powerscourt and dispatched to his home at Enniskerry, Co. Wicklow. This was to become the source for a number of introductions to English deer parks in the late 19th century and early part of the 20th century. Several sika were sent to Melbury Park, Dorset, in 1880, where a number are still to be seen, and 16 years later in 1896, a small breeding herd was introduced to Brownsea Island.

Any hopes that these deer would remain on the island were quickly dashed. Several animals swam to the mainland and, in conjunction with escapees from a later introduction to a park at Wareham, founded the sika herds that are now so well established throughout much of west and south Dorset. Chris believes that the population of the Purbeck peninsula is now in the region of 8,000 sika and expanding.

Brownsea Island is a gem. If you are interested in viewing and hearing a wide variety of birds, including avocets, little egrets and black-tailed godwits, and would like to see red squirrels or simply enjoy a reminder, on a miniature scale, of England as it once was, you should definitely pay Brownsea a visit. Brownsea Island Nature Reserve is open daily (10am to 5pm) from March to October and there are regular half-hour boat services from Poole Quay and Sandbanks. Access to the Dorset Wildlife Trust reserve is 150m from the National Trust quay. There is a small charge to enter the reserve for non-DWT members.

Dorset Wildlife Trust is running a special membership offer for Shooting Times readers ? 18 months’ membership for the price of 12 months if you pay by Direct Debit. Visit www.dorsetwildlifetrust.org.uk and quote the code Partners 2011.