Osprey
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 with 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, a previous president of the BNSS (1916-1917), donated the specimen in our collection 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. In addition, the clearing of woodland nesting sites for agricultural expansion, combined with the rising use of pesticides that contaminated water sources, has exacerbated a decline in prey populations 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 eggs again until 1959 due to the disturbance of their nests by humans, 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 in July 2017, Roy Dennis Wildlife Foundation and the Birds of Poole Harbour transferred eight juveniles from Scotland to Poole Harbour, with the aims of breeding by 2020. Initially, the aim was to transfer sixty Ospreys over five years, but this was later extended. After a few false starts, one Osprey fledged in 2022. One pair has now successfully bred for the last 3 years.
