How a hawk learned to use traffic signals to hunt more successfully
112 comments
·May 27, 2025krisoft
throwanem
I see pigeons and sparrows dodge cars by inches, too. For that matter I do the same myself! Sparrows hawk insects out of the air, and I believe starlings also. Predicting motion would need to be second nature, I think. Like skillfully catching a ball, but much more so and between your teeth...
vikingerik
Well, there is survivor bias there, of course; you don't see the ones that didn't learn to dodge...
PunchyHamster
You do, you can usually find those on your passenger seat
throwanem
Correct. They would be visibly laminated to the pavement or smashed in the gutter. It does happen, but less often than ospreys drop fish in late summer.
stanmancan
We call that evolution
im3w1l
But it makes you wonder why they cut it that close. What benefit they get from it. I can think of several plausible reasons but none that is self-evidently true.
xg15
At the main bus port of my city, you can see heaps and heaps of pigeons casually strolling right in front and even below the buses while they are still driving. There definitely has to be learned behavior for the pigeons to be so completely devoid of fear in that situation.
blarg1
I once threw a tennis ball straight up, just as a bird happened to be flying past, it rolled right and dodged it by a cm.
throwanem
I don't really know what it's like to be a bird, of course, but I have to imagine their subjective experience of duration differs greatly from ours.
HeyLaughingBoy
Squirrels, OTOH...
Neywiny
I'm not an ornithologist but I think birds integrate some onboard magnetic compass sensors. So, it would be interesting if they can pick up the magnetic part of an electromagnetic wave of the radio. Seems very low likelihood but would be cool.
Edit to add https://www.sciencedaily.com/releases/2023/08/230828130356.h... . What frequency were you at? Seems they may actually be listening.
IAmBroom
"Picking up" and "discerning useful data" are very different.
I'm not even talking about "deciphering". Even knowing that energy in a certain bandwidth means planes about to leave seems a large jump - and a radio tuned to a station is likely an order of magnitude more stringent than an animal's sensory abilities.
PunchyHamster
I'd imagine the fact they are high frequency rather than constant field would make it impossible
xg15
I read somewhere that migrating birds often use human infrastructure - roads, railways, power lines, etc - as landmarks or even "route markers" for their migrations.
A bit of a shower thought, but I think you can probably generalize that idea: Most birds spend a significant part of their life in the air, looking down onto human-designed landscapes. The aerial view of our cities is probably as familiar to them as our neighborhood streets are to us.
But unlike Google Maps, they see the city moving - all the cars, pedestrians, trams, railways, etc. It seems likely to me that if this is what you see day-in, day-out, because it is literally the space you are living in, you will pick up some general patterns in what you see and might even start to experiment how those patterns can be exploited.
nomand
a bird's eye view :)
lloeki
> Cooper’s hawk is on a rather short list of bird of prey species that have successfully adapted to life in cities. A city is a difficult and very dangerous habitat for any bird, but particularly for a large raptor specializing in live prey: you have to avoid windows, cars, utility wires, and countless other dangers while catching something to eat every day.
Peregrine falcons adapted quite well, and they're much more sizeable. That said, their size make them very apt to hunt pigeons, so this could be a less risky niche to hunt for; I mean, pigeons usually fly higher up than sparrows.
techas
Live stream of Peregrine Falcon nest at the top of Sagrada Familia in Barcelona:
https://www.youtube.com/watch?app=desktop&v=TMRRsBh5GDI
I spend too much time on this...
twic
The Black Redstart evolved to live in holes in cliffs and the like, and never used to be widespread in the UK. After the second world war, cities all over the south were bombed out, and they moved into the deserted, derelict bombed areas in great numbers. As the bomb sites were cleared and the cities redeveloped, their habitat was eroded. But at the same time, Britain was de-industrialising, and they moved into the abandoned factories in the North. As those now get redeveloped, they are losing their habitat again.
hshdhdhj4444
You have the story of Flacco the owl who lasted 1 year in Manhattan after having spent his entire life in captivity.
https://en.m.wikipedia.org/wiki/Flaco_(owl)
Even his death (due to a collision with a building) was likely less because of his ability to survive, since he managed to learn all the skills necessary, and more due to the fact that his primary food source, rats in and around the city, were laden with rat poison.
We have consistently and regularly underestimated non human animals cognitive abilities which is frankly strange if you understand evolution since it would be strange for only humans to have a certain evolutionary feature such as intelligence and every other species to not have it at all.
nashashmi
> underestimated non human animals cognitive abilities
I think humans have done precisely what humans do: misunderstand. Unlike other animals, humans don't have the ability to understand creatures they have not studied for long periods of time.
We know animals are intelligent. But we don't know what intelligence means. Is it something we can use? no? then it is something we ignore. And it is most likely something we disrespect.
hackeraccount
There are Peregrine falcons in my city. I remember walking downtown one time and seeing one on the sidewalk with a pigeon in its talons. All the commuters and I just walked around it. Really weird somehow.
throwaway422432
Melbourne, Australia has a family of falcons living on the roof of 367 Collins St in the CBD. You can find some of the falcon cam footage on YouTube.
vidarh
London apparently has a high density of them (but high density still only means something like 40 breeding pairs), and some people are all excited about the prospect that they can do something about the rapidly rising wild parakeet population...
morkalork
I'm having a hard time squaring away the image of grey gloomy London also being overrun with colourful tropical looking birds, I had to google it and see.
lloeki
Interesting, around here raptors hunt high, and if prey falls to the ground they abandon it; too dangerous to go down in the streets.
IAmBroom
That's a hawk vs falcon hunting difference, not a city vs countryside one.
Quail won't take off if a falcon's shadow passes over them; they'll burst if a hawk's does.
glxxyz
I almost ran one over turning in a car park in Edmonton. Backed up and it was still standing on the pigeon glaring at me. I drove around.
guerby
There's a couple of peregrine falcons with a live streaming webcam on top of Cathédrale Sainte-Cécile in Albi, south of France
spike021
The City Hall of San Jose, CA, currently has a couple peregrine falcon young in a nest on its roof i believe. It’s relatively high up for the area.
pdabbadabba
> Peregrine falcons adapted quite well, and they're much more sizeable.
I'm not sure what you mean. As far as I am aware -- and according to every source I've looked at in the last few minutes -- Peregrine falcons and Cooper's hawks are about the same size (length and wingspan are within 1-2 inches).
throwanem
Peregrines are somewhat smaller and much more lightly built. I live in a nesting pair's territory which often sees transitory Cooper's; they're easy to distinguish both in flight and at rest. Male Cooper's are more peregrine-sized and hard to tell from sharp-shinned hawks sometimes, but that is an ordinary enough sexual dimorphism in birds.
Interestingly, while peregrines and accipiters like Cooper's share a habit of taking passerines in flight, the response of potential prey seems to differ. I frequently see songbirds mob a Cooper's; I can't think offhand of a time I've seen them respond to a peregrine other than by crypsis.
lloeki
Sadly we don't have Cooper's around here so I have no experience with them, hence why I looked them up (see nearby comment) and according to that source found out they were on the smaller size and much smaller weight.
Around here the only ones who would dare mob a peregrine would be crows.
lloeki
> according to every source I've looked at in the last few minutes
I may be mistaken but that's what I found:
https://en.wikipedia.org/wiki/Peregrine_falcon
> The peregrine falcon has a body length of 34 to 58 cm (13–23 in) and a wingspan from 74 to 120 cm (29–47 in)
> Males weigh 330 to 1,000 g (12–35 oz) and the noticeably larger females weigh 700 to 1,500 g (25–53 oz)
https://en.wikipedia.org/wiki/Cooper%27s_hawk
> Total length of full-grown birds can vary from 35 to 46 cm (14 to 18 in) in males and 42 to 50 cm (17 to 20 in) in females. Wingspan may range from 62 to 99 cm (24 to 39 in), with an average of around 84 cm (33 in)
> In northern Florida, males averaged 288 g (10.2 oz) and females averaged 523 g (1.153 lb). In general, males may weigh anywhere from 215 to 390 g (7.6 to 13.8 oz) and females anywhere from 305.8 to 701 g (0.674 to 1.545 lb), the lightest hawks generally being juveniles recorded from the Goshutes of Nevada, the heaviest known being adults from Wisconsin
(not putting the full regional rundown, just the biggest entry)
skipkey
In my neighborhood in the East Valley in Phoenix, I’ve seen Cooper’s hawks, kestrels, peregrine falcons, zone tailed hawks, merlins, and one immature bald eagle. Along with the numerous turkey vultures and the occasional black vulture.
Etheryte
Plus pigeons are not exactly known for being incredibly smart or agile, so if you're big enough to take one down, you probably won't struggle too much for food.
Modified3019
Pigeons are actually known for being very agile, and are able to do vertical takeoffs and evasive maneuvers like a backflip loop immediately after takeoff, which is precisely to evade predators like falcons.
City pigeons just tend to become fat, lazy and used to suppressing their flee response around traffic and people.
KineticLensman
Pigeons fly surprisingly fast and can outfly smaller raptors in a straight line. A stooping (diving) Peregrine will usually win. Its strike may decapitate the pigeon which tends to minimise the struggling
morkalork
Except for the part where pigeon racing is an entire sport that relies on both their speed and intelligence
jfk13
Except that it's not clear whether the intelligence† that underlies their homing ability is equally effective in helping them evade predators.
†Is "intelligence" even the right word here? I don't know. Much depends on how you define it, I guess, combined with the unknowability of the pigeon's own mental processes.
devoutsalsa
I once wrote a personal’s ad in SQL on Craigslist, back when they had that section. A DBA replied and asked if I wanted hawking. She had a Cooper’s hawk. I met her at a commercial park in a Saturday morning. She was driving a Honda CRV, the hawk was in the front passenger seat, and I hopped into the back seat.
She started driving and spotted some crows. The hawk saw them as well. Wearing a “don’t kill me either your claws” glove, she moved her hand to the hawk, who gleefully jumped on. She rolled down her window, stuck the hawk outside, and it was basically a drive by shooting with a bird bullet. This happened three times.
My most vivid memory of this was her ripping the crows apart into pieces and putting the then into a bucket, like it was sushi you’d order from KFC.
speakfreely
I've reread this a few times and I still can't figure out if there's something wrong with me or something wrong with this post.
cs02rm0
I once wrote a personal’s ad in SQL on Craigslist, back when they had that section. A DBA replied and asked if I wanted hawking.
I feel I have to reply, but I have no idea what to say.
deadbabe
For starters he could post what the hell his SQL query was.
patrick41638265
Reading the first paragraph of this made me think how LLMs must feel when someone tries prompt injection on them
dmd
And you didn't get married!?
3cats-in-a-coat
And this, kids, is a Markov chain.
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qingcharles
This is peak HN.
sodokuwizard
If true, then this hawk has more pattern recognition than many humans I've encountered over the years.
johngossman
If you are interested in these birds and live in the Seattle area, the Urban Raptor Conservancy has a wealth of information:
https://urbanraptor.org/research/seattle-coopers-hawk-projec...
There are over a hundred nesting pairs in Seattle.
munchler
Surely the author teaches at Rutgers University, not “Rudgers”.
c-linkage
It's spelled like it sounds! :D
troelsSteegin
Local to south Jersey it's "ruckers".
cameronh90
I’m from south Jersey and have never heard of this “ruckers”. Is it near Ouaisné?
louky
>> As of 2025, he also teaches mathematics at Rudgers University.
In the second sentence.
Not even run through an AI grammar-checker?
xandrius
What's wrong with that?
Philpax
I believe it's Rutgers, not Rudgers.
cryptonector
Spelling, not grammar. Perhaps OP meant that the comma is unnecessary?
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panny
I've watched karasu carefully wait for a yellow light to drop his walnut in an intersection. The last car passing cracked his nut, then he had time to gather the meat during the light change before other cars came along.
Someone
Some crows in Japan do something like that, dropping nuts on/near a pedestrian crossing, and waiting for a green pedestrian light. See https://youtu.be/BGPGknpq3e0?feature=shared
Neywiny
Looks like Karasu is the Japanese word for crow. So this is an interesting linguistics exchange
msephton
Came here to post that one. I remember watching it so clearly and it's stuck with me.
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nosmokewhereiam
Japanese crow-dactles would put candy in wrappers into crosswalks and let cars run over them. They may have used the sounds of the crosswalk. I have no sources, just anecdotal.
They were big birds. Intimidating wingspans, if hit by cars on their highways: they damaged cars, etc.
fortran77
There's a better writeup of this here:
https://www.theatlantic.com/science/archive/2025/05/hawk-new...
bayindirh
Or, the original paper:
https://www.frontiersin.org/journals/ethology/articles/10.33...
AStonesThrow
Coincidentally, American pedestrians are using HAWK signals to navigate road traffic successfully.
I have a similar story. I was taxiing a Cessna 152 at LHBS. It is a big grassy field. On that day there were a large flock of black birds sitting on the grass. I made the usual radio call to announce that I'm leaving the runway and taxiing to the tie-downs when the birds flitted away just between my airplane's nose and my destination. The birds outside of that "road" by roughly a wingspan distance remained on the ground and kept doing whatever they were doing. And the ones who took to the air settled back a short distance away from my future path.
Now just to clarify I don't think the birds were listening on my radio call. The way I explained it to myself is that they were observing airplanes coming and going long enough that they learned that if an airplane hesitates at that point the next thing they will do is to turn towards the tie-down area. Or maybe it was just randomness. Or maybe as I was making the radio call I already started turning and they just got scarred away by my engine noise.