Ospreys on the move for their summer feeding
Ospreys are on the move at present. With the sole exception of Antarctica, these large birds of prey occur worldwide and are unusual in that their diet consists almost exclusively of live fish.
Also known as the ‘fish eagle’ and the ‘fish hawk’, the Osprey is neither an eagle nor a hawk. It appears to belong to a distinct group of birds and to be the sole representative of that group. Authorities on bird classification are still not in agreement on where to classify Ospreys and the sole species is often split in two: the Western Osprey that occurs in Ireland and the Eastern Osprey found in Oceania and Australia.
Ospreys differ from eagles and hawks in that, like owls, they have a reversible outer toe that allows them to grasp with two toes in front and two behind. They also have barbs on the pads on the soles of their feet; adaptations to help them grip slippery fish.
The fish they feed on must be at or near the surface; say a Pike or a Perch in an inland lake or a Grey Mullet or Flounder in a coastal estuary. The Osprey can hover like a Kestrel as it scans the water surface. Large eyes and excellent eyesight help. Its all-white underside helps to camouflage it from its prey below. Powerful flight and great agility are required to approach the highly-alert prey.
When it judges the moment to be right, the predator powers down to the water surface and with precise timing it plunges in feet-first, thrusting its four large, razor-sharp talons into the water to strike and seize its slippery prey, pluck it deftly from the water, take off, gain height and fly to a perch to devour its prey.
Like Swallows, Ospreys are summer visitors to this part of the world from their wintering grounds in Africa. They arrive around March and leave again in September. They are rare visitors to Ireland and don’t breed here. They are also rare in Britain, but small numbers do breed in Scotland, building huge stick nests on the very tops of tall Scot’s Pine and Douglas Fir trees.
Ospreys migrating north at this time of year are most likely to be seen in coastal areas and are pretty distinctive due to their large size, long wings, white underparts, and combination of white head-crest and dark eye-stripe. Hopefully they will be back again in September.