Osprey prey
I SPEND MOST summer Saturdays fishing. I have lots of company; at least one other human, sometimes as many as three in two boats, not counting a host of cyclists and noisy ramblers who travel through glorious country seemingly unaware of anything but their ceaseless chatter.
Other company is much more interesting, especially early in the morning before the hordes arrive and disturb things. Once an otter surfaced with a splash by my boat, contemplated me and, realising I too was a fisherman, ignored me while he finished his breakfast. I am less delighted by the cormorants though I have to acknowledge their sagacity for they have learned that man, having removed most of the fish from the sea, has stocked lochs and lakes from Land’s End to John o’ Groats with delicious and easily (for a cormorant) caught trout.
Then there are sandpipers, curlews and redshank, grey and pied wagtails, and black grouse coo their amorous invitations from a nearby and invisible lek. Swallows dip in the loch and, high above swifts scream and wheel. Warblers, stonechats and yellowhammers flit among the brooms and once a flight of crossbills settled I an old Scots pine. I am sure I would catch more fish if only I paid less attention to the birds!
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There are kestrels, sparrowhawks and occasionally a hen harrier but of all the raptors my most constant company are a pair of ospreys.
These world-wandering birds are fascinating; the only continent where I have not seen them is Antarctica and that’s not surprising for it’s the only one that Pandion haliaetus never visits. They are, so my books, tell me exclusively piscivorous; but long ago I learned never to believe all I read in print. They certainly eat fish and are remarkably adept at catching them. On days when no trout dimple the surface of the loch the ospreys circle, crook-winged, above me searching the water inch by inch. Sometimes a bird will stop, hover and watch minutely before resuming its hunt. Then it will see another target, hover again, drop a few feet judging depth and speed, before making its dive. Watching from below it seems that the predator is immediately over the fish but that is not so. The moment it launches its attack it does not drop vertically, as a kestrel would, but makes a shallow forty-five degree dive to hit the water with an enormous splash. For a moment the great bird is invisible in spray and then, with a huge effort it lifts itself free of the loch scattering water all around. Often it has a fish in the iron hooks of its talons. Then the bird somehow manages to rotate the fish so that it points head forward as the captor heads for home
Occasionally the osprey makes a mistake; they have been known to attack a fish so large they cannot lift it from the water – then both bird and fish may die. Often the fish escapes; several of the fish I net into the boat bear bilateral scars as evidence of an encounter with an unlucky osprey.
But are ospreys exclusively fish eating? One Saturday no fish rose either to my flies or to tempt the aerial fishermen. Then I witnessed something I had never seen before. The slightly smaller male gave up his fruitless fishing and returned again and again to a patch of heather twenty yards from the loch. Clearly something fascinated him for he hovered watching intently just as a kestrel does when hunting voles. At first the bird swithered about thirty feet from the ground, then dropped to a mere six feet. Then he pounced vertically, just as a kestrel will, and quite unlike his angled dive for a fish. Unfortunately he dived into dead ground and I could not see if he killed, or what his prey might have been.
It seems they do not just eat fish. A friend suggested frogs, but frogs do not much care for heather a foot deep. I wondered about voles and sought advice from a more learned ornithologist than I. He had seen a similar thing on an island off West Australia where ospreys occasionally took small marsupials, but added that he had never seen this in Scotland.
Can anyone offer an explanation? Please write to me c/o comment or give me a ring on 01887 840380.
© Robin Hull
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