Falcons’ hunting style ‘unusual’
Kā rearea have been observed hunting in unusual ways. Globally, falcons are renowned for using acute eyesight for highspeed aerial attacks in daylight.
New Zealand falcons regularly hunt like this, but Te Papa ornithologist
Dr Colin Miskelly recently collected observations of rare hunting behaviour, including a night-time attack on the ground under a deep forest canopy.
It occurred on Motukō rure, a tiny island in Lake Hauroko in eastern Fiordland on February 4 last year.
The falcon was perched on a log about 1 hour, 45 minutes before sunrise. An adult mottled petrel left its colony and walked rapidly downhill in thick undergrowth.
‘‘The falcon bounded down a sloping tree trunk towards the petrel, and then attacked it below the crest of a low bank,’’ wrote Miskelly and two colleagues. ‘‘Flailing wing tips were visible for about three seconds, before the falcon re-appeared.’’
The description was precise because the attack was recorded on a video camera. Motukō rure is usually free of mammal predators, but in mid-2020, stoats and mice were detected. DOC staff installed a variety of cameras and traps to end the invasion, and one captured the attack. The petrel apparently survived.
‘‘It’s such an unusual behaviour and goes against everyone’s awareness of what [falcons] do,’’ Miskelly said in an interview.
Meanwhile, Miskelly was on another tiny island off Anchor Island in Dusky Sound, Fiordland, on February 25 last year. He disturbed a falcon with a freshly killed and still warm mottled petrel at 4.40am, almost two hours before sunrise.
The kill wasn’t witnessed, but it was clearly at night and under a dense canopy of olearia bush. The falcon flew off.
A completely different attack style was observed by then-DOC ranger Andre de Graaf on Takapourewa-Stephens Island in the Marlborough Sounds. Takapourewa contains the world’s largest colony of another species of petrel, the fairy prion (1.4 million pairs).
During daylight in late December 2013, de Graaf was on the veranda of the ranger’s house and observed a female falcon land nearby and run under a hedge. She emerged moments later with a prion chick.
‘‘The adult female returned to the hedge on two further occasions, and each time she was observed entering a prion burrow and disappearing out of sight, before emerging backwards five- to 10 seconds later dragging a live prion chick with her beak,’’ reported de Graaf, a co-author of the paper in the journal Notornis.
De Graaf witnessed several similar raids and inspected one of the burrows. ‘‘It had a wide entrance leading to multiple prion nest chambers, all of which were beyond the length of his arm.’’
Prions are well studied. Fledglings don’t leave their burrows until mid-January, several weeks after the attacks witnessed by de Graaf, the authors wrote.
Ornithologists and observant DOC rangers are regularly in kā rearea territories and these two behaviours have not been previously recorded.
So it is possible that individual birds have figured out these hunting styles but not passed them to their offspring, Miskelly said.
Overseas, falcons are known to hunt by artificial light, including in major cities. They also hunt by dim light at dusk and dawn, and probably by moonlight. In Japan, a peregrine falcon killed a duck 40 minutes before sunrise, but may have been assisted by light reflecting off snow.
‘‘These circumstances were unlike the complex environments under dense canopy where we recorded New Zealand falcons attacking,’’ the scientists wrote.