By Keri Murrell
Ospreys are the only raptors whose diet consists of predominantly fish. Consequently, they are capable of spotting prey whilst hovering up to 300 ft (91.4 m). This makes their eyesight 3-5 times better than humans. Ospreys hunt in two ways. Frequently used is the vertical dive. They plunge toward the water from heights between 30-100 ft (9.1- 30.5 m), its wings half folded. Finally, at the last moment it throws its feet forward, diving up to 3.2 ft (1 m). Alternatively, they glide along the water grabbing its prey in passing. Ospreys have specialised feet: with four elongated toes Each have tiny spicules (spines) underneath, allowing a better grip on its prey. It’s fourth outer toe is opposable allowing the Osprey to move the prey to face forward with two toes on each side, reducing air resistance during flight.
Threats
Lord Malmesbury, the previous president of the BNSS (1916-1917), donated the specimen in 1946. It is believed the Osprey was shot on the 29th September 1822 at Avon Cottage. During this period, it was popular for Victorian collectors to shoot birds to not only obtain specimens for taxidermy but to collect their eggs too. Consequently, the Osprey population declined. Combined with the removal of woodland nesting sites for agriculture, and the increased use of pesticides ending up in the water, initiating a decline of prey. The Osprey became extinct in England as a breeding bird by 1840, and absent in Scotland from 1916 to 1954.
Reintroduction
In spring 1954, a Scandinavian pair of Ospreys successfully reared two chicks, initiating a natural recolonisation of Scotland. Although returning annually, they did not lay again until 1959 due to harassment of nests despite RSPB protection. Thus, in 1981, fines and prison sentences were introduced. Following this, at Rutland Water, England, a breeding population was introduced in 1999. This occurred through the translocation of chicks from Scotland. Locally, Roy Dennis Wildlife Foundation with the Birds of Poole Harbour in July 2017 transferred eight juveniles from Scotland to Poole Harbour, with the aims of breeding by 2020. Overall, they aim to transfer sixty Ospreys over five years.
