When it comes to birds of prey native to New Zealand, you are limited to four. The barn owl (Tyto alba delicatula), morepork (Ninox novaeseelandiae), swamp harrier (Cicus approximans) and the New Zealand falcon (Falco novaeseelandiae). There are others that have either been introduced and become somewhat established, such as the little owl (Athene noctua vidalii) which was introduced by the Otago Acclimatisation Society in the early 1900s, or visitors/vagrants that have not managed to establish breeding populations i.e. nankeen kestrel, black kite and the white-bellied-sea eagle. New Zealand was also home, once upon a time, to the Haast’s eagle (largest, heaviest eagle ever described, weighing up to 17.8 kg and had a wingspan up to 3 metres), the laughing owl, and the Eyles harrier, whom are all sadly now extinct.
Of the native birds of prey, the barn owl, is so rarely seen it can be separated from the other three as being a bit of an outlier. It has only ever been recorded breeding once in New Zealand, which just sneaks it in under the label ‘native’. These birds arrived in New Zealand by a variety of means, however, some are most certainly windblown stragglers from Australia. There are only 13 records for New Zealand including the one breeding pair documented near Kaitai.
The morepork is a nocturnal owl whose call resembles its name-sake. During the night you can often here something eerily calling for ‘moore pooork’. The Maori name for this bird is ‘ruru’. These guys are very endearing and I hope to get some good shots of them later down the line.
For the purpose of this short blog, however, my main focus will be on the remaining two native species, the swamp harrier and New Zealand falcon. The two are often confused with one another. To see a table outlining the differentiating features of the two species see Figure 1 below. Until recently, I had only ever seen the swamp harrier. I can be pretty sure of this, not because of my hot identifying skills, but rather because the swamp harrier is by far more common than the New Zealand falcon and tends to occupy a wider ecological niche.
The swamp harrier is also known as the Australasian harrier and is an opportunistic hunter. Carrion forms a major proportion of the harrier’s diet, however, they do hunt for small, live birds, mammals and insects. If you see a bird of prey on a fence post or eating road-kill, you are fairly safe to assume you have seen a swamp harrier. The bird is the largest of the 16 species of harrier found worldwide. They have long legs, have prominent facial disks and a strongly hooked bill. Although plumage can be variable in colour, generally they have a tawny brown back and typical cream/pale chest when adult, and glide with their wings held in a shallow ‘V’ shape.
On a recent exploit to Bushy Park, Whanganui, we heard, and consequently hunted down two New Zealand falcon (karearea) perching high up in a tree amongst the epiphytes. This was a first for me and a great chance to get some photographs. The New Zealand falcon is widespread in New Zealand, but rare. The falcon is a small bird of prey that feeds mainly on live animals. It is comparable in size to a magpie, so considerably smaller than the swamp harrier. The falcon has relatively short rounded wings and a long tail, adapted for fast chasing flights in pursuit of prey within dense forests. The harrier on the other hand has a slow beating flight and broad wing tips. The falcon has dark eyes whereas the adult swamp harrier has yellow eyes. Falcons also have a distinctive dark moustache-like stripe running vertically down from the bill.
The New Zealand falcon is the only endemic surviving bird of prey left in New Zealand. Its population is uncertain but is likely to be between 5,000-8,000 individuals. The New Zealand falcon exists in three forms that vary in size, colour and habitats. The ‘Bush Falcon’ (650 pairs) is found in North Island and northwestern South Island forests, the ‘Eastern Falcon’ (3,150 pairs)occupies the open country of the eastern South Island, and finally the ‘Southern Falcon’ (200 pairs) inhabits coastal Fiordland, Stewart Island and the Auckland Islands. ’bush falcons’ as well as ‘eastern falcons’ are currently regarded as nationally vulnerable, whereas the ‘Southern falcon’ is now nationally endangered. Its rarity is down to the following threats: predation, habitat loss, disturbance, development impacts, human persecution, and electrocution. The New Zealand falcon, like all falcons, do not build a nest, but instead make a scraping on the ground in which the female will lay a typical clutch of 2-4 eggs. With the introduction of predators, like rats, stoats, possums, cats and dogs, ground nesting birds have taken an especially large hit. Falcon also make scrapings on rocky outcrops and in epiphytes of emergent forest trees. We found this pair in and around large epiphytes at Bushy Park Sanctuary, so perhaps these falcon have made some wise choices.
Identification and Comparison of NZ Falcon and Swamp Harrier
|Karearea NZ Falcon||Kahu – Harrier Hawk|
½ size of Harrier
300 – 500 grams
|Black-backed gull size
|Description||Dark and fast
Black/dark brown above – barred below
Brown bar on face (like a moustache)
|Generally slow flying
Juveniles are dark brown
Get paler with age
|Flying Away||Rump is dark coloured||Cream rump visible|
|Soaring||Very fast wing beats
Wings flat for short time
|Wings held in shallow “V” for lengthy periods|
|Flight Characteristics||Flies fast – rapid wing beat||Slow flight. Often flap-glide-flap|
|Hunting||Very fast – stoops
Chases smaller birds
|Searches slowly into wind.
Lands on carrion
|Typical Prey||Small birds
Rarely eats carrion
|Flight Silhoutte||Pointed wings
Angled back like an arrow
Slightly rounded tail
Wide wing span
Table and information courtesy of the Raptor Association of New Zealand.
Figure 1. Table taken from Marlborough Falcon Trust website.
References and Further Reading
New Zealand Birds Online – Barn owl http://www.nzbirdsonline.org.nz/species/barn-owl (Retrieved 12 Dec 2016)
Wingspan – NZ Birds Of Prey / Native / NZ Falcon http://www.wingspan.co.nz/birds_of_prey_new_zealand_falcon.html (Retrieved 12 Dec 2016)
Department of Conservation – New Zealand falcon/kārearea http://www.doc.govt.nz/nature/native-animals/birds/birds-a-z/nz-falcon-karearea/ (Retrieved 12 Dec 2016)
Bushy Park Sanctuary http://www.bushyparksanctuary.org.nz/ (Retrieved 12 Dec 2016)
New Zealand Falcon http://www.nzfalcon.org.nz/home (Retrieved 12 Dec 2016)
Marlborough falcon Trust – The Differences Between The NZ Falcon And The Harrier Hawk http://www.mfct.org.nz/content/falcon-hawk-differences.html (Retrieved 12 Dec 2016)
Te Ara – Page 3. New Zealand falcon http://www.teara.govt.nz/en/birds-of-prey/page-3 (Retrieved 12 Dec 2016)