Monitoring the "Narrabeen Ospreys"
Ospreys, Pandion haliaetus, are a large fishing hawk wich can be found on every continent with the exception of Antarctica. Their willingness to create their large nests, composed mostly of sticks but occassionally antlers and even hoola-hoops, in close proximity to humans has endeared them to nature lovers across the world. These birds are spectacular to observe as they elegantly snatch fish from just beneath the surface of lakes and seashores and sometimes plunge well within the waters for a kill. Interestingly, their toes are arranged so that one of the front digits can rotate to a "two-forward-one-back" arrangement, to facilitate easier carriage of their slippery prey. The Osprey is listed as "Vulnerable" in NSW (A Vulnerable species is one which may become Endangered without appropriate habitat management.).
In recent years, a pair of Osprey have taken to nesting in a large pine tree adjacent to Narrabeen Lakes but have failed to raise any young to date. This is not unusual for this species, as they may take several years before attaining success.
Narrabeen Lakes is a large body of water fed primarily by Deep Creek and Middle Creek and lies between Warriewood and Narrabeen on the coast. Prior to development along the coast, Narrabeen Lakes were open to sea, but are now subject to blocking due to the appearance of a large sandspit resulting, some claim, from sand and silt movement subsequent to human development.
In 2006 the Warringah Council contracted a dredging company to re-open the entrance to the lakes. This necessitated operating in close proximity to the nesting Ospreys. I was sub-contracted to observe and record the behaviour of the Ospreys and to determine whether undue or noticeable disturbance took place as a result of this activity. Two possible disturbing factors under consideration were: increased and noisy activity, resulting from a constant flow of trucks carrying sand and two large dredging machines working throughout the daylight hours seven days a week, and; an increase in silt in the lake's waters which might hamper the Osprey's foraging.
The monitoring involved observing the birds from before sunrise to after sunset 2 days a week over the 6 week period and recording all facets of their behaviour. A detailed report was presented to council at the conclusion of the reporting period.
The period of my contract ran from November 10, 2006 to December 22, 2006.