You don't need to travel to the Serengeti to have a David Attenborough moment. Earlier this week, Linton and I had the most bizarre encounter with a titipounamu family, just down the road at Zealandia. What unfolded was a shock to the conservationists monitoring these tiny cute borbs. Tiny they are, but apparently also deadly. The following story isn't for the faint of heart - I've put the worst below some white space that you'll need to scroll past so you won't accidently see anything you don't want to. Only view if you managed to watch Bambi without crying. Further warning, this isn't an official scientific account - some parts are shamelessly anthropomorphised - this might be more upsetting to some of my readership than the murder itself.
Titipounamu (rifleman, Acanthisitta chloris) are the smallest bird found in Aotearoa. A couple of years ago, a small founder population was translocated to Zealandia, and they've been breeding well ever since. They're bigger than a hummingbird by body-size, but shorter because they have no tail to speak of. I think of them as big bumblebees with about three feathers. These birds are cute! Many of us have enjoyed seeing Melissa Boardman's gorgeous photos of fledglings all snuggled up on a branch together - adorable! Having heard through the grapevine that there were fledglings about, I was hoping to get some cute photos too.
But what I got was a lesson in how nature really works. Looking adorable is an illusion. These birds can be vicious - and deadly - fighters. Usually their efforts are spent on preparing their insectivorous dinners, which can take some preparation, including tenderizing and guts removal. A titipounamu demonstrates the process in the video below (trigger warning for caterpillar lovers).
To set the scene, imagine a lovely warm calm spring afternoon in Wellington. OK, I know you can't, but sometimes the impossible happens. We'd spotted the fledglings earlier in the week (on another impossibly lovely day), and had already gotten a super-cute photo (the one leading this story), but I had plans for more. Entering the Te Mahanga Track, we immediately came across them. With Linton's super-sharp hearing (which is pretty good for an old fella), we tracked them to a forested mossy bank.
The "victim" - fledgling GY-RM (green over yellow bands on the left and red over metal on the right)
After getting some super-cute borb (the technical term for a cute round bird) photos, we suddenly noticed that two were fighting on the forest floor, tumbling down the bank through the leaf litter. The lighting was not great, so please forgive the poor photography. Conservation ranger Kari Beaven and titipounamu volunteer Melissa Boardman have since filled us in on the family relationships, which reveals an unexpected story.
"Awww cute," we thought, " they're play fighting." But no, for a minute or two, these two siblings were fighting as if their lives depended on it. On review of the photos, they were going for the eyes and necks. Mama came down a couple of times, but hard to know if she was trying to break it up or egging them on. Either way, they kept fighting. This slideshow could have been taken at an MMA arena. The action occurs in less than a minute but they are so tiny and fast that it's like time moves slower for them than us - real-time video is impossible to follow - it's just a flurry of feathers and leaves. It's the still photos that reveal their moves. The contenders are GW-RM (Green over White on the left leg and Red over Metal on the right leg) and GPu-RM (Green over Purple on left, and Red over Metal on right) - there are so many legs and bands in these photos that it can be hard to work out which leg is which.
We pick the fight up after they've tumbled down the bank into better light. The contenders are GW-RM and GPu-RM.
GW-RM has it's foot around GPu-RM's neck, while being attacked in the face.
Someone has taken a tumble, but it's a great opportunity to see a tiny tail, which is usually hidden by the wing feathers, it's so short.
Eyeing up the most vulnerable body part to go for next.
And we go for the neck stomp!
GPu-RM thrashes about to try and push off GW-RM, and Mama has appeared (top left).
Beak-to-beak rapier action, with a foot to the face to push back the foe.
GPu-RM appears to get the upper hand briefly.
But GW-RM responds with a stranglehold.
GPu-RM grabs GW-RM's beak and goes in for an upper cut using a leaf as a shield.
But is not successful and is pushed off.
GW-RM works on a counter offence.
And we're back to more rolling and tumbling.
So many bands and legs to keep track of! Note the pretty kōtukutuku blossoms on the ground too - these tiny flowers give some perspective to the size of the titipounamu.
Feet locked in combat as the fight continues.
Eventually they break and disappear, and we try to find where they went. Over the next few minutes we have various sightings of the family, and Linton captures a particularly funny moment.
GW-RM looking innocent (and unscathed) after the first fight.
An unassuming GW-RM doesn't notice that GPu-RM has snuck up behind. Nek minnit GW-RM receives a karate kick up the bum that sends him flying. Photo by Linton Miller.
The next drama for me occurs over the stream. I spy two fledglings high on a branch. This time, it starts with the other two siblings from this nest of four. Check out this slideshow which summarizes some brief but important clues we need to understand the motivation for the crime.
"Feed me!" (GR-RM, right to GY-RM, left)
"Dude - you're old enough to do it yourself - see this is what you do" (GY-RM)
"See how easy that was? Yum-yum"(GY-RM)
"That's mine - gimme!" (GR-RM)
"Dude -back off!!" (GY-RM)
"No, I want it - gimme!" (GR-RM)
"Dude, like get out of my face!" (GY-RM)
"Now look what you've done...." (GY-RM)
"You're gonna die!!!" (GR-RM)
The slides show GR-RM (presumed female fledgling, right) begging to GY-RM (presumed female fledgling left) high on a branch. GY-RM forages something tiny from a nook in the branch but doesn’t share and is attacked and both go down off the branch. A few seconds later GY-RM lands safely. But not for long. GR-RM launches another attack while GY-RM is perched on a fern frond. They tumble to the ground. Our cameras struggle to find focus in amongst the leaves with all the movement, but the bands are bright and allow identification. We then realize they've tumbled into stream - GR-RM and GY-RM are still going for it in the water! This slide show captures what happens - fortunately GY-RM manages to escape, but with GR-RM in pursuit.
Shockingly they're fighting in the water. These tiny birds apparently have good buoyancy.
GY-RM (bottom left) uses its feet to push the aggressor GR-RM (top right) away.
It's a frantic fight to get out of the water.
But GR-RM get's a foot around.
As GR-RM flails around to attack, GY-RM sees a gap and makes a break for it.
They both dart back into the undergrowth.
Mama and Papa are also in the area, along with the other two siblings, not seeming to care what's going on. Mama even has a bath in the stream. We also have adults from another nearby nest, which made us thought it was a territory dispute, but titipounamu are "normally" coorperative. In review, the only fighting is among the four siblings - the other family doesn't get involved.
In the meantime, we're distracted by this impossibly cute titipounamu posing on a mamaku frond. He's the Dad in from the neighbouring nest/territory but seems to be minding his own business.
A couple minutes later, the battle resumes in the stream between GY-RM and GR-RM. Trigger warning for the following content… Together we capture shocking footage of a murder... I know many of you will not want to see this, so I've put some white space below so you know not to scroll past it. For those that choose to continue, you'll also need to click to see the more confronting video. But I understand if you may want to stop here.
From behind a fern leaf, GR-RM forces GY-RM back into the water. GR-RM appears to have her foot on GY-RM's neck forcing her under. (Photo by Linton)
Followed by a sharp peck. (Photo by Linton)
GY-RM is not in good shape. (Photo by Linton)
GY-RM lifts a wing to try and right herself. (Photo by Linton)
And also raises a foot. (Photo by Linton)
She gets her head up, only to be forced down again. (Photo by Linton)
GR-RM is using both legs to push her down. (Photo by Linton)
And down she goes with a splat. (Photo by Linton)
GY-RM is really struggling now. GR-RM continues to peck and push her down. (Photo by Linton)
Those beaks are deadly! (Photo by Linton)
Here it appears she's also using her legs to hold GY-RM under. (Photo by Linton)
More savage pecks continue, even once it's obvious that GY-RM has sadly drowned. (Photo by Judi)
But that doesn't stop the attack. (Photo by Judi)
The two birds drift downstream. (Photo by Judi)
As is usually the case with crime footage - the evidence is blurry and disjointed and behind the bushes. But we've watched enough CSI to know you can magically enhance the images using impossible resolutions and industrial strength software (in other words, I've denoised, sharpened, and cropped and we just have to do our best to puzzle out what's going on). In this slideshow, I've pulled some key images from Linton's blurry burst as they (sadly) show the demise. I've added some of mine at the end, but although I'm in a better position, I'm not as quick on the draw. My video shows the aftermath.
In this slideshow we see GR-RM drowning her sibling GY-RM, by repeatedly forcing GY-RM's head under the water using her feet to grab and push, and sharply pecking around the head. She uses her wings as a counterbalance as there is some resistance from the surface water tension. Not content with killing her sister, GR-RM continues to peck at the dead body, using her beak like a rapier, as they both float down the meandering stream, while we look on in horror.
A curious thing is that part way through the battle, while GY-RM is still alive, Mama appears on the scene about 20-30cm up slope (under a leaf) but appears inffectual or uninterested in stopping the melee. Once it's all over, Mama can be glimpsed leaving the scene of the crime. Seconds later, she's spotted bathing in the stream again. Peace returns, and Melissa reported that the following day the family is happily foraging and flitting about as normal.
Not having much to do with titipounamu conservation, we had no idea how normal this behaviour might be. But it sounds like we inadvertently captured a very unusual moment. The Conservation Team is working to unpack what went on. Siblicide in the nest across is well known in many species of birds and is well-reported on, if not well-understood. But as Melissa observed, these fledglings had been happily cuddled up in the nest together. They had fledged a number of days ago and were able to mostly fend and forage for themselves. There have been other instances of titipounamu aggression captured (e.g., a gang of seven beating up and killing another), but not a recorded case of siblicide (murdering a sibling).
Kari says that the parents have started laying a new nest nearby, but they are still feeding their fledglings. My uneducated guess is that the frustration and aggression may have to do with the reduction of parental feeding (weening), forcing the fledglings to up their game and be more self reliant. The whining and begging we see in kākā fledglings is a noisy reminder of the weening process (not to mention human babies) - it's not a popular time for any species.
But titipounamu fledglings, according to Kari, are adept at feeding and foraging for themselves so the energy cost to do that should be less than fighting a sibling for morsels. But although energy costs will be a factor, birds may be as likely to fall for cognitive biases as we humans are? Perhaps the fledglings were hungry and impatient, and the immediate reward of getting what someone else had seemed worth the effort? From my training in human psychology and from lived experience (which I'm sure we can all relate to!), humans will frequently choose a course of action that is not rational, and is biased and flawed. Rational thinking takes time and effort and is hard. If you were hangry enough, then maybe you'd murder a sibling too?
(If you love thinking about cognition and decision making, do read Kahneman's book "Thinking, Fast and Slow" for a whole new perspective - I'd must dig in and find out if these ideas have also been applied to bird and other animals).
I'll add to this story if and when we learn more.
Thanks for reading - I hope you found it interesting, even if disturbing. I'd love to hear if you've encountered anything similar or if you have thoughts as to what was going on.
P.S. if you'd like to check out my art and photography featuring titipounamu, check out this collection. They make perfect TinyArt pieces too (if none are in stock, do get in touch as I can make them to order).