Bird social behaviour

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Al Capone Junior
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Bird social behaviour

Post by Al Capone Junior » Sat Sep 11, 2021 10:39 pm

Not really an insect behavior thing, but cool anyway.

When you mow a yard here in texas, especially if the grass is quite high, there may be many insects, inc many grasshoppers, who are disturbed by the mower. They jump out of the way of the mower as you mow.

Now the interesting thing is the birds, specifically the evil black birds, the crows and ravens. In some locations, when you mow, the birds don't seem to notice or care. But in a few specific locations, the birds show up out of the clear blue sky as soon as you start to mow. They are having a feast on the insects that are escaping the mower. Out of the frying pan and into the fire, so to speak.

So I speculate wildly, but with some limited evidence, that the evil black birds in these certain locations are exhibiting culturally transmitted behavoir. I think most birds have not figured this feast out, because this phenomenon is not at all common. Usually when you mow a yard, no birds show up, even if there are plenty of disturbed bugs. But it reliably happens every time at a couple of locations that I happen to sometimes mow. These two locations are also pretty close, within a couple of miles as the crow flies. So possibly there are birds that show up at both places.

A confounding factor is that if there are not plentiful grasshoppers, and few insects are disturbed by mowing, then this phenomenon can't happen.

The null hypothesis here is that I am full of bird sh.t. A distinct possibility.

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Aitch
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Re: Bird social behaviour

Post by Aitch » Sun Sep 12, 2021 6:12 am

Well...

Corvids are supposed to be among the most intelligent of birds, so no reason why they shouldn't learn to recognise the signs of a possible feast. And teach their offspring?

However, do they stay in family groups or do the generations spread out to their own territories? If the former, it would explain why the behaviour hasn't spread. And provide another nail in the coffin of morphic resonance?

Is this interesting enough for someone to do a PhD on it? Or failing that, for them there mods to split it off into it's own thread?
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Al Capone Junior
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Re: Bird social behaviour

Post by Al Capone Junior » Sun Sep 12, 2021 5:30 pm

Aitch wrote:
Sun Sep 12, 2021 6:12 am
...for them there mods to split it off into it's own thread?
Is there a birds thread? Mods could split and give a better title, perhaps "birds and stuff they do"

Al Capone Junior
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Re: Bird social behaviour

Post by Al Capone Junior » Sun Sep 12, 2021 5:49 pm

I recall (perhaps shakily) that the evil black birds can have upwards of 250+ distinct, repeatable calls, but that chimps who learn sign language only learn 200 or so signs. I think that this may indicate the eventual success of the diabolically evil plans the black birds will soon unfurl upon us

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Bird on a Fire
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Re: Bird social behaviour

Post by Bird on a Fire » Mon Sep 13, 2021 8:13 pm

Moved some posts from the "Insect Behaviour" thread.
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Bird on a Fire
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Re: Bird social behaviour

Post by Bird on a Fire » Mon Sep 13, 2021 8:26 pm

Al Capone Junior wrote:
Sat Sep 11, 2021 10:39 pm
Not really an insect behavior thing, but cool anyway.

When you mow a yard here in texas, especially if the grass is quite high, there may be many insects, inc many grasshoppers, who are disturbed by the mower. They jump out of the way of the mower as you mow.

Now the interesting thing is the birds, specifically the evil black birds, the crows and ravens. In some locations, when you mow, the birds don't seem to notice or care. But in a few specific locations, the birds show up out of the clear blue sky as soon as you start to mow. They are having a feast on the insects that are escaping the mower. Out of the frying pan and into the fire, so to speak.

So I speculate wildly, but with some limited evidence, that the evil black birds in these certain locations are exhibiting culturally transmitted behavoir. I think most birds have not figured this feast out, because this phenomenon is not at all common. Usually when you mow a yard, no birds show up, even if there are plenty of disturbed bugs. But it reliably happens every time at a couple of locations that I happen to sometimes mow. These two locations are also pretty close, within a couple of miles as the crow flies. So possibly there are birds that show up at both places.

A confounding factor is that if there are not plentiful grasshoppers, and few insects are disturbed by mowing, then this phenomenon can't happen.

The null hypothesis here is that I am full of bird sh.t. A distinct possibility.
There was an interesting study recently by the Max Plank Institute of Animal Behaviour in Germany. They were looking at White Storks, which aren't quite as strictly tied to wetlands as the Wood Storks common in Texas. Anyway, they found that when grass was cut, storks reliably arrived from downwind (which they observed using aerial surveys and GPS tracks). They then released "green leaf volatile organic compound mix ((Z)-3-hexenal, (Z)-3-hexenol, hexenyl acetate)" - described in the paper as "the smell of cut grass" and found that it attracted storks. From this, they conclude that the storks were using smell to find these bountiful habitats, and were able to exclude visual and social cues.

I suspect, though, that Al is right that in crows it's a socially learned phenomenon. Corvids are quick learners and highly social, but also quite generalist in habitat use and don't to my knowledge have a great sense of smell. But they do look out for large aggregations of conspecifics and join them. The spatial pattern would seem to fit this hypothesis. It could be that only some birds have learned the association between mowing and insects, or that only some have overcome a natural wariness of humans and machinery (for instance, they might avoid agricultural areas if corvids are regularly controlled).
He has the grace of a swan, the wisdom of an owl, and the eye of an eagle—ladies and gentlemen, this man is for the birds!

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Bird on a Fire
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Re: Bird social behaviour

Post by Bird on a Fire » Mon Sep 13, 2021 9:09 pm

Aitch wrote:
Sun Sep 12, 2021 6:12 am
Well...

Corvids are supposed to be among the most intelligent of birds, so no reason why they shouldn't learn to recognise the signs of a possible feast. And teach their offspring?

However, do they stay in family groups or do the generations spread out to their own territories? If the former, it would explain why the behaviour hasn't spread. And provide another nail in the coffin of morphic resonance?

Is this interesting enough for someone to do a PhD on it? Or failing that, for them there mods to split it off into it's own thread?
It's genuinely not a million miles from what I'm doing my PhD on ;) though I'm working with waterbirds rather than crows.

I think the way information spreads through natural populations is fascinating, and quite often overlooked. We often think about resources like prey or safe sites to shelter, but don't often think about how individuals get information about those resources. For populations that are depending on resources that are highly restricted in space and/or time, information could well be a limiting factor.

There is a period of a few weeks after fledging when corvids tend to stick with their parents and are deliberately "taught" about sites, dangers, prey etc. (At least, they accompany their parents while they deal with those things, and learn through observation.) During the winter, these species often form huge communal roosts with multiple species of corvids (Crow County by Mark Cocker is a wonderful, wonder-filled exploration of the phenomenon). As well as the general safety-in-numbers aspect during the long nights, it's generally thought (though not well empirically confirmed yet) that these roosts serve as "information hubs", with birds able to share information about good places to forage etc.

For species that migrate, tracking studies are showing the importance of "horizontal" social learning for juvenile birds' survival (horizontal = learning from unrelated adults, rather than vertically from parents). One of the starkest demonstrations I've seen followed Lesser Spotted Eagles, comparing a native population with juveniles that were translocated as part of a reintroduction scheme. The native juveniles departed with adults, followed them by a more convoluted route, and arrived in Africa, whereas the translocated juveniles set off earlier, went in the wrong direction, and mostly died in the Mediterranean.

There's two important take-homes from this:
1) animal behaviour is generally a mix of instinct and learned behaviour. For instance, those translocated eagles were setting off in a sensible compass direction to migrate from Latvia via the Suez Isthmus into Africa (as birds that glide on thermals, they're not good at crossing open water). But because they were starting off from Germany, they didn't run into any responsible adults to join up with. (In Blackcaps this initial migratory orientation seems to be a single-locus mutation, so highly evolutionarily malleable).
2) learning doesn't have to be complex - it can be as simple as following a rule of "join with other members of the same species", and then at least you're in the right place. Loads of birds have a very strong instinct to join flocks, which hunters have exploited for millennia via building decoys for wildfowl or making imitative whistles.

Conservationists now consider these social phenomena carefully when planning reintroductions of migratory species/populations. For instance the project to reintroduce Whooping Cranes to North America included teaching them to migrate by getting them to follow an aircraft. They also found that unsupervised juveniles who joined up with adults chose more direct migratory pathways (linkeroo). The reintroduction of Black-tailed Godwits in East Anglia has found that the captive-reared birds soon join with wild individuals after release, and migrate with them to Africa and back.

In longer-lived, higher-intellect species, there's generally a process called "canalization" - juveniles will try out all sorts of stuff, but increasingly specialise in a number of quite specific behaviours. If it ain't broke, don't fix it. This also has important conservation implications: once habitat is lost, individuals quite possibly won't find other suitable habitat even if it's close by. Furthermore, adaptation depends on a constant supply of new recruits, so if breeding success declines the population is really in trouble.

There's depressingly few good studies of this in an age of wholesale habitat loss, but at a local scale, impounding some mudflats in Cardiff Bay caused Redshank survival to decline from 85% to 77% - birds observed to have moved to a new area (only 4km upstream!) had lower body condition, indicating that they struggled to find enough food in their new digs. At a much larger scale, the loss of most of the Yellow Sea in China - a key stopover site in the East Asia-Australasia flyway, is associated with the decline of pretty much all populations that depended on it.

Waders tend to be highly site-faithful, though, whereas other species like corvids may be less so (I'm genuinely not at all sure, especially for US species). Where new opportunities become available, or old ones disappear, it would only take a few individuals to figure it out before the new information can spread through the population. For instance, in the early 20th century UK there was a well-documented phenomenon where Blue Tits (related to Chickadees in the US) learned how to open the foil tops of milk bottles left on people's doorsteps. The behaviour developed at multiple sites and spread through local populations. Recent experimental work suggests that juvenile tits, especially females and subordinate males, are the quickest to learn stuff.

So yeah, despite the length of that post, I really want to conclude by saying that I think social learning is often quite a simple process ("join with others"), pretty ubiquitous (it clearly has a high survival value), and super cool. And on a personal note I always find reading these kinds of local natural history observations pretty stimulating, so thanks for sharing :)
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Re: Bird social behaviour

Post by IvanV » Fri Sep 17, 2021 1:56 pm

When the big field over the road from my house is mowed,* lots of red kites appear. You can often count around 20 or so circling above during the mowing. There can be the occasional other thing joining in, but mostly it is just the kites. I assume this is about flushing out the rodents. But I've not noticed red kites circling over many other hayfields when they are mowed, sometimes, but far from normally.

*The field owners have lots of horses, including racehorses, and the field is carefully managed to produce hay to feed them.

Al Capone Junior
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Re: Bird social behaviour

Post by Al Capone Junior » Fri Sep 17, 2021 10:27 pm

Should be a good day for "buzzards" (actually a local misnomer for turkey vultures). Being that it's about 109 and blaring, lots of stuff should be found dead everywhere. :shock:

Actually them there birds ain't stupid. They are disproportionately hanging around at the lake, river, pond or creek nearest them.

There's a small lake that basically has a concrete bike path all the way around. Ppl and birds interacting, often comically, sometimes a bit crowded.

Big birds, little birds, ducks and geese, house sparrows assimilating ppl into the borg, ravens and crows collaborating on diabolically evil plans, stately vultures high overhead, these will survive the anthropocene, just as they did the Jurassic, asteroid and all.

One night at my gf's apt, I went outside to start up the grill. I disturbed a pigeon-sized bird who has hiding behind a chair. It flew off, perfectly silhouetted by a bright full moon.

Which gave me a perfect view of the bigger bird swooping down from a tree and ... BLAM.

Pigeons End.

Not sure exactly what either bird was, but the big one was probably a hawk.

Hawks are the mafia muscle for the Evil black birds. But they ain't as smart, so it's still the black birds that will soon be our Evil Overlords.

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Boustrophedon
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Re: Bird social behaviour

Post by Boustrophedon » Mon Sep 20, 2021 10:30 am

We threw out some slightly out of date sausages onto the lawn and within seconds the garden was full of crows fighting over them as birds higher up the pecking order grabbed the sausages off ones lower down the order.
One smaller obviously low status bird was sitting on the fence keeping out of the melee, hoping for some scraps, when he saw a sausage just below him that the others had missed. He immediately looked away from it and this is the part I don't understand, he looked right at us, whether to assess us as a threat I don't know, but think not, we were indoors. Then he turned round and looked the other way.
That crow had a theory of mind: He knew if he went for the sausage he'd lose it to one of the others. He also knew that if the others saw him looking at it, that they would work out that there was a sausage there and he would lose it.
Eventually he did the crow warning squawk and flew off across the garden past all the others, who panicked and flew off too. Our crow did a circuit of the house, landed on the sausage and took it up to the top of the fence. Then he looked at us again and calmly ate the sausage. I'd swear he was saying "look, did you see that? Clever me, I got the sausage."
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Tessa K
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Re: Bird social behaviour

Post by Tessa K » Mon Sep 20, 2021 10:48 am

Boustrophedon wrote:
Mon Sep 20, 2021 10:30 am
We threw out some slightly out of date sausages onto the lawn and within seconds the garden was full of crows fighting over them as birds higher up the pecking order grabbed the sausages off ones lower down the order.
One smaller obviously low status bird was sitting on the fence keeping out of the melee, hoping for some scraps, when he saw a sausage just below him that the others had missed. He immediately looked away from it and this is the part I don't understand, he looked right at us, whether to assess us as a threat I don't know, but think not, we were indoors. Then he turned round and looked the other way.
That crow had a theory of mind: He knew if he went for the sausage he'd lose it to one of the others. He also knew that if the others saw him looking at it, that they would work out that there was a sausage there and he would lose it.
Eventually he did the crow warning squawk and flew off across the garden past all the others, who panicked and flew off too. Our crow did a circuit of the house, landed on the sausage and took it up to the top of the fence. Then he looked at us again and calmly ate the sausage. I'd swear he was saying "look, did you see that? Clever me, I got the sausage."
Smart. I've heard of low status primates misdirecting others from something they want but not corvids.

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shpalman
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Re: Bird social behaviour

Post by shpalman » Mon Sep 20, 2021 6:31 pm

molto tricky

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