Williamson's Weekly Nature Notes - September 10

In a good year, 90 per cent will return next spring to breed, but last year only 70 per cent returned.

The 'fish eagles' were caught out over the Atlas mountains and the Spanish sierras by snowstorms.

Even so, about 500 birds are airborne right now from the north. Only about a score of them are noticed in Sussex.

They are mainly spotted at Arlington and Weir Wood reservoirs, and at various ponds in Ashdown Forest and along the Adur and Arun valleys.

One of my favourite places to see them is over the Great Deep on Thorney Island on the West Sussex/Hampshire border.

They may spend two weeks with us or they may go through in a day.

Looking up at them as they glide high overhead, you can tell them from the buzzard by their white chin, belly and legs, and their speckled white-and-black wings.

A buzzard is browner beneath. Ospreys also have wings with a sharper kink at the 'wrist'.

But they are quite different birds to buzzards. Placed in a family of their own '“ the Pandion '“ they have peculiar feet.

All four toes are of equal length but the outer toe is able to swivel forwards or backwards as required.

The feet are also covered with spines instead of flat scale '“ all the better with which to grip slimy fish. Fish catching is not easy and sometimes things go horribly wrong.

In Germany, a large carp was netted in a lake, the catchers noting something very odd about the fish '“ the remains of an osprey's skeleton was embedded in its back.

Then, in 1839, A E Knox reported the extraordinary adventure enjoyed by a shepherd boy near Rottingdean, "a small village three miles from Kemp-town.

"While tending his flock near the cliff, he observed an osprey rising with difficulty from the sea, and bearing in his claws a large fish, with which he alighted near the edge of the precipice.

"Running up hastily to the spot, and perceiving the distress of the bird, who appeared incapable of carrying off his prize, or of disengaging himself from it, but looked, as the boy expressed it, as if he was stuck in a trap, he quickly dispatched it with his crook."

The famous Brighton taxidermist Mr Swaysland mounted the osprey on the back of another fish. Where is it now? Better to see a live one this month.