Watch these superbly adapted raptors plunging for fish to feed their young
Mike Dilger’s WILDLIFE SPECTACLES The broadcaster, naturalist and tour guide shares the most breathtaking seasonal events in Britain
OSPREYS FISHING
Many birders describe August as being the quietest month of the year to enjoy our feathered friends. Certainly high summer is the time for quietly raising broods, with many adults additionally keeping a low profile while undergoing their annual moult. But for anyone suffering birdwatching withdrawal symptoms this month, then good news and views can be provided by the osprey, and the frankly marvellous spectacle of it fishing for its supper.
Slightly longer bodied than a buzzard and with much longer wings, this large raptor is specialised to eat nothing but fish. Ospreys are purely summer visitors to our shores, with most overwintering in the wetlands of Senegal and The Gambia. BirdTrack reveals that birds can appear back in Britain by late
February, but the main arrival occurs in early April, with males often turning up at least a week earlier than the females.
Often using the same treetop nesting site, year upon year, most pairs appear to be faithful. Changes of mate are only thought to occur when one of the pair has died or returns so late that in the interim its ‘other half’ has found a replacement. Following an affirmation of the pair’s bonds (through courtship), the female proceeds to lay a clutch of eggs.
Incubation lasts for about 37 days and the eyrie is fairly quiet as the female undertakes the lion’s share of sitting while the male keeps her provisioned. As soon as the young start hatching, his fishing responsibilities ramp up. Even when the chicks fledge, after about 53 days, both parents continue to provide food for their offspring for at least a month or more, before beginning their migration south.
Did you know?
If ospreys fail to breed they
will often start to build a
new nest, known as
a ‘frustration eyrie’
Favoured fishing grounds for most ospreys are believed to be within a 15km radius of their nest but occasionally it may approach double this distance. Certainly, in the Scottish Highlands, where the vast majority of pairs still breed, ospreys will fish on rivers, lochs, lochans and estuaries, with fish farms increasingly becoming favoured hunting grounds.
Ospreys occasionally hunt from perches with a watery view, but mostly they scan while in flight, and initially from a height of 30m or even more. Interspersing flapping with gliding, their head, at this stage, can be seen constantly swivelling a
