Bird Watch

NOW we have a better chance of seeing an osprey in the UK than at any time in the past 150 years.

They were considered extinct here by 1916, having suffered persecution for most of the previous century at the hands of egg-collectors, trophy hunters and gamekeepers.

The recolonisation of Scotland has been a long process since about 1955 when a pair nested at Loch Garten, but there are now estimated to be more than 200 breeding pairs in the UK. Although the vast majority of them breed in central Scotland, they are now breeding in several sites outside of Scotland.

Rutland Water in Leicestershire has had breeding ospreys since 2003 thanks to a reintroduction programme, and the Lake District (since 2001) and North Wales (since 2004) can now boast nesting ospreys from natural expansion of the Scottish population.

This is all testimony to a long-term, determined conservation effort stemming from a handful of nesting attempts in the Scottish Highlands more than 50 years ago.

In line with the increasing breeding numbers in Scotland and the north of England, ospreys are appearing on passage in ever greater numbers around the country. As they spend the winter in Africa, we see the birds either in April and May on their northward journey, or from around late July to early October when they are heading south.

During the late summer and early autumn they often stop off for a few days in locations at reservoirs and coastal sites that provide good fishing opportunities, and this is the best time to look for a bird locally. In spring, sightings are often much more fleeting, with the birds heading quickly north to their nesting sites.

It might sound a little fanciful but it is not unreasonable to start placing bets on where the first ospreys in the south of England will nest. It is unlikely to be very soon, as breeding ospreys tend to nest very close to where they were reared, but I am sure it will happen as long as the UK population continues its expansion.

As with many large birds of prey, the same nests are used over and over again for many years, which is why staff at the osprey project at Bassenthwaite in Cumbria were so surprised this week when the returning ospreys decided it was time for a change. After breeding for seven years on one side of the lake they have now moved to the other side.

They usually pair for life and return to the same spot each year, so this switch is a real shock.

If you have ever seen an osprey nest you might realise why. They are not subtle constructions, an enormous pile of sticks more than a metre wide that takes a lot of time and effort to build.

They are also quite choosey about the precise location. A new nest is clearly not a small undertaking. This is perhaps why a young pair of ospreys will sometimes choose a site and build a nest one year and breed in it for the first time the following year '“ ospreys are usually three years old before they start breeding.

In many locations in the UK and indeed round the world, the birds are given a helping hand. Artificial platforms are put up at suitable-looking sites in the hope they will build their nests on top.

There is no reason to believe in years to come we may have our own osprey platforms alongside wetlands in Sussex but for now we will have to be content with those fly-by migrants.

This was first published in the West Sussex Gazette April 30. To read it first, buy the West Sussex Gazette every Wednesday.