Rotorua: falcons and other birds

April 3, 2017 • 10:00 am

My amiable and gracious hosts in Rotorua are Geoffrey Cox, a terrific artist who specializes in natural history (website here, more on his art later) and his wife, Barbara Hochstein, a crack radiologist. Today (Monday) Geoffrey took me to—among other places—the Wingspan National Bird of Prey Centre in Rotorua, New Zealand. The goal was to see the raptors, but especially the New Zealand falcon or kārearea (Falco novaeseelandiae), the only falcon in New Zealand and the country’s only remaining endemic dirurnal bird of prey (there’s one species of owl left, but all other daylight hunters have gone extinct save the swamp harrier, which is found in other places).

The Centre is not a zoo: its goal is to rehabilitate injured birds of prey, to breed them and introduce them back into the wild and, if an injured bird can’t be set free, to use it for breeding and for educating the public. They take their mission exceedingly seriously, and I was quite impressed.

Male and female falcons are quite dimorphic, with females larger (the male weighs about 2/3 as much as the female). I don’t know the explanation for this size difference, but it’s is seen in other New Zealand birds, like some of the extinct moas. If you know the explanation, please put it below!

Here’s a picture of the size difference between female (left) and male from the classic Buller’s Birds of New Zealand:

The falcons are seriously endangered, with far fewer falcons than kiwis living in New Zealand. One of the factors reducing the population of these birds is their habit of nesting on the ground, characteristic of many birds in New Zealand (there were no mammalian or reptilian predators to destroy eggs before humans arrived, and nesting in trees has its dangers).

The falcon’s closest living relative, according to Wikipedia, is the South American Aplomado falcon (Falco femoralis). 

To train birds to hunt in the wild before release, they are handled and trained by a falcon expert—one person per bird—and are flown every day. (I was told that without daily flying, in three days they’ll revert to being totally wild.) Today they were flying a young male, and they did a great demonstration.

Look at this lovely bird!

Below: male photographed on the handler’s gauntlet. The bird has huge eyes, like the peregrine falcon (whose eyes are as large as a human’s), and can apparently see eight times better than we. As a display in the Centre noted, a person in a car can read a license plate on a car 50 meters ahead, but a falcon can read a plate (if it could read!) 400 meters ahead.

The handler let the bird go, and he flew out of sight into the trees in the distance, spooking a bunch of sparrows on the way. We couldn’t see him at all, but he could see us, for as soon as the handler raised her glove or put out a lure, the bird came winging back.

Falcon training with a lure:

The bird can, from a long distance away, spot a tiny piece of meat placed atop a fencepost. It comes in low at a glide, a foot or so above ground  level, and then glides up to the post, using gravity and extended wings to help it stop.

Several children were asked if they wanted to hold the falcon, and nobody wanted to; but after a little girl volunteered, they all wanted to.

They then asked for adult volunteers, and of course I shouted, “Me, me, me!” Here’s the highlight of my day (and one of the highlights of my life), with the photo taken by Geoffrey. The bird also landed on my arm, but the talons didn’t hurt.

This is a bigger female awaiting her turn to fly:

A female falcon graces the New Zealand $20 note:

And they told us this is the exact female whose portrait was used for the note above:

Here’s a feathered skeleton of a New Zealand falcon attacking a blackbird.

New Zealand used to have two native owls in historical memory. Sadly, the laughing owl (Sceloglaux albifacies), or whēkau in Maori, was extinct by 1914 due to hunting, deforestation, and predation on eggs and young by introduced rats and stoats. The remaining owl, of which there was one in the Centre, is the morepork (Ninox novaeseelandiae), also found in Tasmania:

Geoffrey has a particular interest in the extinct moas and their predators, and perhaps their main predator was Haast’s eagle (Harpagornis moorei), a monstrous raptor with a wing span of 2.5-3 meters and a weight of up to 15 kg.

Here’s Geoffrey with a silhouette of a Haast’s eagle. He’s made models of both moas and parts of this raptor; I’ll show those in subsequent posts.

Although moas were larger than Haast’s eagles, the big flightless birds were easy prey. Here’s Wikipedia‘s description of an attack:

Haast’s eagles preyed on large, flightless bird species, including the moa, which was up to fifteen times the weight of the eagle. It is estimated to have attacked at speeds up to 80 km/h (50 mph), often seizing its prey’s pelvis with the talons of one foot and killing with a blow to the head or neck with the other. Its size and weight indicate a bodily striking force equivalent to a cinder block falling from the top of an eight-story building. Its large beak also could be used to rip into the internal organs of its prey and death then would have been caused by blood loss. In the absence of other large predators or scavengers, a Haast’s eagle easily could have monopolised a single large kill over a number of days.

And a reconstruction of the eagle attacking moa.

The eagles died out about the same time as the moas: about 1400 AD. The moas were driven to extinction by Maori, who craved their meat; and without prey the eagle couldn’t survive.


UPDATE: Reader David Coxill sent me two swell photos related to the above (but in another country), and a description:

Your latest piece about the New Zealand Falcon reminded me of our visit to the Lakeland Bird of Prey Centre in Cumbria .
The Falconer asked if any one wanted to let a bird land on their arm . This little girl volunteered, and I managed to get a photo of the bird just landing on the glove .

I think the bird involved was a Red Tailed Hawk [Buteo jamaicensis].

The falconer at work: a man happy in his job .

54 thoughts on “Rotorua: falcons and other birds

    1. “Morepork”, as you might expect, is from the sound of the bird’s hoot – a distinctive two-note call.

    2. When Jerry is at my place he’ll be able to hear a morepork (Maori – ruru) frequently at night. There’s been one living nearby for about three years now.

      The sound of the call is, well, “pleasant” is probably the best word I can come up with. I really like it anyway.

      1. For a moment there I thought I understood. I know what a pheasant sounds like. Sorry about that.

  1. Wish there were still Haast’s Eagles!

    Sexual dimorphism in size is very common in diurnal raptors, with the female larger than the male. The most likely explanation is that this widens the pair’s niche, with the female better able to handle large prey and the male better able to handle smaller prey. The male should be the smaller one since it will not have to make and carry eggs, which take up a lot of space and weight. But almost certainly the full story is more complicated, since some hawks are not so dimorphic.

    1. I should add that the evolutionary mechanism that drives this dimorphism is probably competition between the sexes, rather than “what’s good for the species” which has no selective effect on any given individual.

      1. Another possible cause mentioned is sexual selection for smaller size (for proper bonding of pairs).

        Recently saw where falcons were used to protect the grape vineyards from the birds that do damage. Apparently it takes 11 years to become a master falconer.

    2. I was going to offer the rather bland speculation that females were larger because they had to be large, so to manage the carrying of eggs and to provision them with a good load of nutrients. Larger eggs are more likely to hatch robust chicks, and so on.
      But your description is much more interesting.

    3. Yes, but we see the same dimorphism in several of the extinct moas, which were herbivores. Females could weigh up to three times what the males did. Now why is that?

      I seriously want to know!

              1. I said this in a meeting today in response to a peer’s fear that the data in our scrum board could generate questionable perceptions:

                “I only have two things on the board. Does it look like I’m not working? Maybe. Do people say I’m not working? Sometimes. Do I care? No.”

                Only one person laughed and laughed raucously. 🙂

    1. More open grassy habitat now than formerly, I’ll bet, and barn owls don’t like dense forest. Human modification of the habitat has probably made colonization more likely.

      1. @John Dream on! I understand that due to an accessibility lawsuit filed by the American Council of the Blind, future bill designs will have a tactile design included for all bills [‘cept the $1 & $100]. Also larger, higher-contrast digits + greater colour differences between denominations. But I think that’s as far as it will go.

        What they should do of course is make the different denominations in distinct sizes, but I doubt that will happen.

        They also need to get away from depicting iconic historical buildings & people, but I doubt that leap will occur when there’s demands for ignored minorities to get a turn. No exotic animals in your future 🙂

        I wonder if a physical currency will exist in 100 years? Electronic wallets allow anonymous transactions & I can see a day when beautiful postage stamps & coins/notes are solely collectors items. Unfortunately.

      2. New Zealand “paper” money is actually made from some sort of plastic.

        Note the transparent window with hologram above Jerry’s fingers in the photo.

        1. Yes, Canadian money is polymer too. I think a lot of countries are using polymer now, which makes Falco’s song about Mozart harder for the kids to understand: …no plastic money anymore; die Banken gegen ihn 🙂

    1. Don’t quote me, but I’m pretty sure NZ and Canadian money is made by the same company. Both constantly have the most advanced anti-counterfeit stuff built in too.

      1. The $5 NZ banknote was designed and printed by the Canadian Banknote Company (I didn’t even know there was such a place — I just thought there was the Canadian Mint). As a kid, my Nana sent me $5 NZD and I remember I really liked the hidden hologram thing that changed in the picture. I have no idea what happened with that banknote. Maybe I spent it in NZ when I went there as a young adult.

  2. Love the falcon and their story. The close-up picture of the falcon on the handler’s glove is very nice. I also like the picture of the little girl with the falcon. She’s a trailblazer!

    Haast’s eagles killing moas doesn’t seem unlikely when you consider the better documented and verified accounts of Golden Eagle kills that have accumulated over the past 10 – 20 years. A few years ago I read of an account by researchers studying reindeer.

    After gathering data of all sorts for a long period of time there were a small number of reindeer deaths that could not be explained. Then someone noticed that these unexplained deaths all had certain things in common. Stab wounds into vital organs (may have been specifically the heart, can’t recall). A researcher finally got curious enough to spend the time following reindeer herds around long enough, at a distance, to try and observe one of these mystery deaths.

    They eventually observed one, and it turned out to be a Golden Eagle. The eagle selected a reindeer and then repeatedly attacked it at high speed striking talons first at a particular spot on the reindeer, behind the shoulder if I recall correctly. The eagle then followed the reindeer at leisure and waited for it to collapse from blood loss. Examination of the body revealed the same stab wounds into vital organs (the heart?) that the mystery deaths had.

    1. Fascinating story of death by Eagle. By the sound of it, the bird had been doing this long enough to have evolved a specific technique for this kind of prey.

  3. A “crack radiologist?” — Surely Barabara does displaced fractures as well?

    On a serious note, I’ve always assumed that Maoris took an active — and pragmatic — role in the extirpation of the eagle. A bird capable of taking down a large moa would readily apply the same technique to other large bipeds as its usual prey became rare.

    1. There are in fact a number of Maori legends that can (of course without being able to prove it) be interpreted as giant eagle problems. They usually take the form of a winged monster menacing the tribe,and a brave warrior going out and slaying it. The monster goes under various names – Puakai, Hoi Hoi and in the Rotorua region, in my opinion, Kurangaituku. The one problem with the last id is that giant eagle remains have never been found in the North Island, but I’m prepared to argue that they must have been here, although perhaps in small numbers.

  4. Glad you made it to Rotorua! I hope you get a chance to see the hot springs there and to go to Te Whakarewarewatangaoteopetauaawahiao to see a Maori haka 🙂

    1. I went to a hot springs spa. Totally affordable but that was a really long time ago. It was great to go in the pool of hot springs water but it will stain some jewelery so you have to be careful.

  5. James is right go to Pohutu Geyser which is a geyser in the Whakarewarewa Thermal Valley, Well worth the visit

    1. It’s appallingly wet weather in Rotorua at the moment, although nearly 20C, all because of remnants from Cyclone Debbie.

      One benefit, if Jerry has good waterproofs, is that the geothermal areas will be particularly steamy and spectacular.

      1. I visited them for the first time in the winter (July) and it was pouring out! Still thought they were pretty neat though and the boiling mud still bubbled. 🙂

  6. A tentative explanation for smaller males in raptors.
    To raise a chick both parents have to work hard. As an illustration, they often produce only two eggs, the second one a kind of insurance policy. The older chick, if doing well, generally eats its younger and smaller sibling. Raising two chicks is extremely rare.
    Thus we may conclude parental investment is high and comparable for both sexes, unlike in mammals. Raptors do not (as far as I know) fight for mating ‘rights’, and with sharp talons and beaks, a very aggressive fighting strategy may not pay off, especially since there is no great prize in the form of a ‘harem’. They are basically monogamous.
    All this, of course, only explains why males are not larger then females (see Jerry’s earlier posts on sexual selection), not why females are larger then males in most raptors.
    However, this is speculative now, eggs are more costly than sperm. A healthy, big female may lay a ‘better’ couple of eggs, or exhaust her reserves less, than a small female.
    There could indeed also be a widening of niche, diversity of prey size, as Lou Jost mentioned above. But that would not explain why it is systematically the female that is larger. If niche widening were the sole cause, we would expect an about 50/50 distribution.

    1. The NZ swamp harrier mentioned above, generally lays 3 eggs. The youngest chick is usually fed to the older ones by the mother herself. In ‘difficult’ years even the second one is fed to the first.

  7. Marvelous hawks.I am envious – having a hawk up close,on one’s arm.
    Once ,several years ago, on a woods and fields walk, we rescued a red tail, took it to a local raptor care center. (Vermont Institute of Natural Science). When it recovered – from stress, starvation – I was invited to its release. A thrilling moment I won’t forget.
    Thank you for the lovely bird and NZ photos-

  8. Remarkably, DNA evidence suggests that Haast’s Eagle was most closely related to the Australian Little Eagle, which as its name suggests is one of the smallest eagle species.

    It seems to have undergone a very rapid size increase after colonizing New Zealand, presumably due to the lack of competition and abundance of moas and other large prey.

    Such a pity we can’t see it alive. But then, with a very close living relative, perhaps “Jurassic Park”-style technology might be able to re-create it one day.

  9. The hawk in the last photo is a Harris’s hawk I believe, not a red-tailed hawk. Very different beast-they are cooperative hunters. The new Planet Earth II series has amazing footage of a group engaged in a cooperative hunt. I am off to Arizona in a couple of a weeks and high on my list is to be able to observe Harris’s hawks. If I get any good photos I will send them in.

    1. Your mention of Planet Earth II reminded me of a new factoid I learned from it regarding Golden eagles. Golden eagles are the 2nd fastest bird known, behind only the Peregrine falcon. They had a wonderful sequence showing a Golden eagle in a dive. If I recall correctly the speed was over 300 kph. A quick google search gives a max speed for the Peregrine of 389 kph (242 mph) and 320 kph(200 mph) for the Golden.

      I thought that was really impressive given the difference in size between a Peregrine and a Golden. That’s gotta hurt getting hit by a Golden eagle.

  10. Hi ,thanks for clearing that up .
    I have got some photos of Raptors i took in Texas ,Arizona and Nevada ,most of them are perched on top of telegraph poles ,don’t know the Species .

  11. I have no doubt that the Haast’s Eagle was big enough to have taken Children,or Adults, if it could kill a Moa , I’m sure a person would be pretty easy, Must have been dodgy wandering around New Zealand in the early Days.

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