A group of international wildlife tourists received a bonus during their $13,000 trip to Australia – the sight of a family of peregrine falcons going about their business in southern Tasmania.
The peregrines became a talking point for the tourists even though technically speaking they did not see them in the flesh.
En route from the state’s north-west to Bruny Island, their coach made a call at the home of their guide, wildlife biologist Nick Mooney, to view a live ‘‘feed’’ from a nest of peregrine falcons where he had installed a wi-fi camera.
Mooney had scouted the sight and installed the camera before the breeding season got underway at the start of spring, and had subsequently watched and heard the falcons’ courtship ritual and mating, then the female laying and incubating eggs before the actual hatching.
By the time the mainly American tourist party had arrived the three chicks – all females judging from their large size – were doing well and swapping their downy white plumage for one resembling juvenile birds.
Mooney started the project mainly to determine the effectiveness and benefit of a more hands-off approach to monitoring breeding peregrines, compared with one that involves visiting the nest. There are always concerns that these nest visits – which involve abseiling down cliff faces because Tasmanian peregrines nest on ledges – are stressful for these excitable birds.
Mooney is trying to establish just how much information he can gain about peregrine breeding – the diet of the young, for instance, and how often they feed – from using a camera, as opposed to actually collecting samples of prey during breeding.
Besides giving the tourists something to talk about and some images to take home with them, there has been a pay-off for the children of a local primary school who have received a live feed of the peregrines’ behaviour to aid them in their natural history studies.
Mooney hopes next year to establish a website for the peregrines, and meanwhile he is providing a regular series of still pictures for the Tasmaniantimes.com website to plot the peregrine family’s progress.
The peregrine – the world’s fastest creature that can swoop, or stoop, at speeds in excess of 300 km/h – is of particular interest to visiting American birdwatchers because at one time it was a seriously threatened species in their country, where the bigger sub-species is called the duck hawk. Shortly after World War II it fell victim to the widespread use of the harmful pesticides DDT and dieldrin. These man-made chemicals, which build up in predators at the end of the food chain, was subsequently banned, and peregrine populations have slowly recovered.
In Tasmania, however, the peregrine did not suffer the poisoning fate on the same scale, and despite a period of heavy persecution has maintained healthy populations over the years, including in the general Hobart area.
I didn’t know it until I visited Mooney’s home recently to view the peregrines via his
Nestcam that the species here holds the record for the oldest known nest of a bird. Carbon dating of mummified remains of peregrines at an old nest site in the north-west of the state shows it was used at least 19,600 years ago.
Meantime, Mooney’s monitoring of the peregrines is already throwing up some fascinating information about them, not least their diet. Mooney has established that introduced starlings are forming about 96 per cent of the food source of ‘‘his’’ birds. At the time of my visit he estimated the three chicks and their parents had so far eaten 300 starlings between them.
He said that when he first started studying peregrines in the 1970s, starlings only formed about 50 per cent of their diet in such rural areas. The latest figures indicate that the starling population is steadily increasing, and so it features more prominently.
Other birds that have been taken by the peregrines, however, include skylarks, noisy miners, an eastern rosella, lapwing, black-faced cuckoo shrike, blackbird and even a hard to catch musk lorikeet.
Something unique to camera study has also been seen. Peregrine chicks reach their maximum weight a week or so before fledging and then trim down. It’s always been thought this is because the parents reduce feeding to induce flying but Mooney has recorded the parents delivering at the same rate and it seems the chicks become more excited at the prospect of flying and less interested in feeding as a result. Therefore, they lose weight.