Masters of the sky
We may have lost our giant eagle, but New Zealand still has two ‘hawks’, one of which is the acknowledged aerobatics supremo.
When english priest and poet Gerard Manley Hopkins penned his tribute to The Windhover he could just as easily have been writing about the New Zealand falcon. Of all the birds in the New Zealand bush, karearea, the falcon, is supreme in aerial mastery and aerobatics.
Capable of outflying a small aircraft (a diving falcon reaches speeds of up to 200kph), this Red Baron of the southern skies is also a consummate predator. It spurns carrion, preferring to take its meat fresh often on the wing. Falcons are intelligent and adaptable hunters, varying their technique according to the opportunity at hand. Their killing repertoire includes prolonged chases through dense bush, contour-hugging prey searches, screaming dives (‘ stoops’) and surprise attacks, where-prey are plucked out of the sky literally without knowing what hit them.
The falcon’s dedication to the art of hunting is almost legendary. Tales of prize pullets and family pets being dispatched by marauding falcons are numerous, and impressive. One tale concerns an Otaki woman who had let her pet cockatiel out of its cage while she did some gardening.
“What’s wrong, Billy?” she called, noticing the bird acting strangely.
There was no time for a reply. Billy was being decapitated in a nearby tree.
Another falcon took 19 pigeons in two weeks, before it was caught in a chookhouse munching on a hen.
With its reputation as a fearless aggressor, it is little wonder that the New Zealand falcon (called the spar‑ row hawk, bush hawk or quail hawk by European colonists) has been, and in some cases still is, regarded as an unwanted pest by such people as farmers and pigeon fanciers. Declining falcon numbers point as much to the effects of human persecution as they do to loss of forest habitat and other ecological factors. Despite the bird’s protected status, its survival is by no means assured.
There are three races of Falco novaeseelandiae: the bush, eastern and southern falcon. Of these, the southern is the rarest, possibly numbering only 100 to 200 pairs. Next comes the bush, with between 400 and 800 pairs, while the eastern is the most numerous — 3000 pairs. These population estimates are, at best, only informed guesses. There are suggestions that falcon numbers could be up to 50 per cent lower, and this summer the Department of Conservation is appealing to the public to supply information on sightings.
Falcons are seldom found north of the King Country. The main ranges of the lower North Island, Nelson and the West Coast of the South Island are bush falcon territory, while on the east of the Main Divide the slightly larger, lighter eastern variety is predominant. The southern falcon inhabits Fiordland and Stewart Island, and even the windswept Auckland Islands sustain a population.
New Zealand is home to a second bird of prey: the Australasian harrier (Circus approximans). This bird, commonly termed the hawk, harrier hawk or swamp hawk, and known to the Maori as kahu, is the one most people have seen soaring over farmland, its wings forming a shallow ‘V’ and its slotted finger-like primary feathers silhouetted against the sky.
Unlike the falcon, which is endemic (that is, found only in New Zealand), the Australasian harrier occurs in Australia and New Guinea, and is the largest of all the world’s harriers.
In Australia, competition with 23 other species of birds of prey has confined the harrier to swamplands. Here the bird has benefited from the clearing of forest and the introduction of mammalian prey such as mice, rats, possums and rabbits, and its distribution is nationwide.
The falcon and harrier, New Zealand’s only diurnal (daytime) birds of prey (raptors), are classified in the order Falconiformes, a group which includes all hawks, harriers, vultures, falcons and eagles. Owls and moreporks fall within the order Strigiformes, reserved mainly for nocturnal hunters.
No one is sure how long the Australasian harrier has lived in New Zealand, but it would appear to have been a relatively recent introduction compared with the falcon. Indeed, it is surprising that more of the Australian birds of prey have not made the eastward journey across the Tasman. Only one raptor seems to be making an effort at the moment: the nankeen kestrel arrived in the late 1960s but does not appear to have established a breeding population.
Falcons were first noted by Europeans during Captain Cook’s voyages to New Zealand. A falcon collected in 1773 by Cook’s ship Resolution was described not in terms of its aerial prowess, but that it was “really delicious roasted.”
Like many of our endemic birds, the New Zealand falcon has characteristics that set it apart from all other birds of its kind. Falcons usually have long wings and a short tail, while true hawks or accipiters have the reverse. Just to be different, the New Zealand falcon is somewhere in between, with shorter wings than a true falcon, and a longer tail. Presumably this combination is the best solution to the requirements of speed and manoeuvrability when flying in a forested landscape.
Apart from size (a female Australasian harrier is nearly twice as large as a male New Zealand falcon) one of the main distinctions between our two birds of prey is their hunting techniques. Harriers are described as having a low wing loading, which means that the ratio of body weight to wing surface area is low. They are therefore best equipped for slow, soaring flight in which they ‘quarter the ground’, using their extremely good eyesight and hearing to detect prey activity.
When prey is sighted, the classic harrier manoeuvre is the dive attack: the bird goes into a full stall, with tail fanned and wings spread wide, then executes a pirouette, half folds its wings and dives. At the last minute the wings are thrown back and talons thrust forward to grasp the prey.
Harriers are capable of a number of other attack modes, but are just as likely to be found tearing at the carcass of a dead rabbit or possum in the middle of a country road. It is a relatively common sight to round a corner and interrupt a harrier mid-feast. The big bird rises from its meal, wings beating laboriously, then sails off across the paddocks.
Some aren’t quick enough, or are deliberately run down, and end up injured or killed. For an injured bird there is little hope of survival in the wild; successful hunting demands a combination of acute senses, swift reflexes and tip-top flying condition. Fortunately, there is a small but dedicated group of people who specialise in ‘harrier repair’, and through their efforts many birds have lived to hunt another day. (See Raptor repairs)
The harrier’s willingness to take domestic carrion such as dead lambs led to the widespread but unjustified belief that they killed live farm stock. For many years a bounty was paid for harriers’ feet, and harriers, like the kea of the South Island, were treated as vermin to be eradicated. In 1986 harriers were declared a protected species, a fact that still seems to be lost on some trigger-happy hunters and landowners.
In contrast to harriers, falcons are high-energy killing machines, perfectly adapted, both anatomically and behaviourally, to the chase. The body of a falcon is no larger than a magpie, but up to 20 per cent of the body weight is flight muscle.
Falcons are extremely intelligent hunters, and appear to consider (and remember) various attack options before choosing one. “Rather like a bank robber,” as one person put it. The most common method is the ‘direct flying attack’. On sighting prey the bird waits for the right moment, then flies in fast and low, either grasping the quarry with talons extended or bowling it over with its knuckles.
The falcon is so fast that the attack is often over in seconds, but longer ‘tail chases’ have been observed to last for up to 15 minutes.
As agile as falcons and harriers are during hunting, it is in their courtship displays that all the aerial stops are pulled out. Courting birds will often soar and chase each other for long periods, sharing thermals to take them high into the skies and then diving back down.
Occasionally, a male harrier will dive on a female, who, just as he reaches her, responds by flipping over on her back and thrusting her feet at him. This spectacular display is a mock aerial food pass; the real thing happens once the female has begun incubating her eggs. During that time the male brings the female’s food to her, but does not usually approach the nest, in order to safeguard its location. Instead, the two fly together, the male slightly above and ahead of the female. He drops a small item of food to her, she flips over and catches it, then returns to the nest.
During courtship harriers emit a melancholy KEEE-a! sound; falcons utter a variety of screeches and whines. Both species emit a sharp, machine-gun-like alarm cry, described as a kek!–kek!–kek! for falcons and a chit!–chit!–chit! for harriers, in situations of danger (for example, if a bird is about to be mobbed by a group of magpies, or if an intruder encroaches upon the nesting territory) or during an aggressive encounter with another bird.
Both birds are also capable of a piercing scream, sometimes referred to as the ‘rusty hinge call’. In the falcon this cry is used by young birds begging food, but also, according to some of New Zealand’s early naturalists, by adult birds when foul weather is ahead. In a paper read to the New Zealand Institute in 1889, W. W. Smith wrote, “the vehement screaming of this hawk when flying high [is] an excellent indication of changes in the barometer…The days on which they perform their high screaming flights are followed by nights of continuous and loud calling of the wekas and kiwis, both of which are equally good indicators of bad weather approaching.”
On a warm afternoon in early spring I visited New Zealand’s most experienced falconer, who lives in a modest house sandwiched between State Highway 2 and the foothills of the Tararuas, just south of Eketahuna.
To say that Rob Wheeldon lives for falcons is an understatement. He shares his living room with a pair of bush falcons (their perch is between the stereo and the TV), spends hundreds of hours building aviaries, teaching raptor enthusiasts and flying his birds, and holds down a job with the National Wildlife Centre at Mt Bruce as well.
The name on the letterbox reads `Tiercel Cottage’, tiercel being the traditional name for a male falcon. The term derives from a French word meaning ‘third’, and was applied to falcons because of a curious size difference between the sexes. In most birds the male is larger than the female; in raptors it is the other way round, with the male roughly a third smaller. There is no convincing reason why this should be so.
Wheeldon is a fount of information when it comes to raptors. He should be; he has been hooked on them ever since he saw his first falcon in Napier at the age of seven. In 1982 he was granted a licence to keep falcons in captivity and three years later triumphed in the first successful breeding of bush falcons in an aviary.
Now he is working on an even more ambitious plan: to operate a breeding programme where the adult birds are not kept isolated, but are in physical contact with the falconer. Wheeldon believes that if he is successful he will be able to speed up the captive breeding process, and perhaps offset the population decline in the wild.
Wheeldon makes no bones about the fact that there’s a battle on for the future of the falcon. Environmental change always hits the top predator hardest. In the falcon’s case, the clearing of native forest has reduced prey density as well as severely reducing potential nest sites. There are numerous factors that go into the choice of a nest site — proximity to water, suitability for taking off and landing, adequate prey density, shelter, to name a few — and if all cannot be met, the birds may not breed at all.
No one is sure just how bad the situation in the wild really is, but Wheeldon is taking no chances. “My commitment is to the survival of the New Zealand falcon,” he says emphatically.
It is a commitment that places his birds ahead of virtually everything else in his life. Whether it means being dive-bombed by angry falcons while counting nests in Marlborough, or giving falconry demonstrations at schools, Wheeldon is doing it.
He still makes time, though, for ‘sideline’ experimental work, such as airport control. Bird strikes at major airports are still a serious problem worldwide. One way of dealing with the problem is to fly birds of prey at the airports on a regular basis, and thus frighten away the scavengers. Wheeldon has flown his falcons at both Wellington Airport and the RNZAF base at Ohakea, but more trials are needed before the effectiveness of falcons as scarecrows can be measured.
That spring afternoon was a special one for Rob Wheel-don. He was going to free-fly Courtney, a young male falcon, for the first time. I could sense the man’s apprehension as he slipped the creance (control) line off Courtney’s legs and carried the bird to a high nesting box. He then walked to a spot some 30 metres away.
Now the test. The bird was free to respond to the falconer… or to fly away and perhaps never return Wheeldon gave a couple of short toots on his whistle and waved a morsel of food. Nothing. Another blast on the whistle. I held my breath.
And there he was. Swooping like a black shadow, seizing the prey and coming to rest on the glove. Wheel-don was beaming. I could have danced.
I was going to ask Rob what draws him to falcons. But watching this bird ride the “rolling level underneath him steady air”, and sensing “the achieve of, the mastery of the thing” made the question pointless.
In my notebook I simply wrote: “The call of the wild.”