Crows hold "funerals" for their dead and this very weird experiment revealed why


#61

What seems very strange about this; and suggests that either I have a very poor intuitive sense of crow mortality(highly likely) or crows fall victim to what we would identify as logical fallacies(also not unlikely) is that the learning behavior; while robust and socially transmitted and so on, seems to involve the wrong lesson.

If I tried to discern sources of danger by carefully inspecting the surroundings when I discovered a human body I’d end up concluding that paramedics are remorseless professional slayers; with grieving family members killing the ones the paramedics don’t finish off first. This would(in the vast majority of cases) be wrong; I’d miss causes of death that are either internal or leave the scene of the crime and develop associations with things that tend to congregate around the dying or recently dead; but not kill them.

In the crow case predation wouldn’t leave an intact corpse(unless interrupted); and deaths of assorted cryptic internal causes wouldn’t have a useful association with resting place(and the presence of some nice carrion would probably attract non-predatory scavengers to develop spurious associations with). This would seem to reduce the value of what is learned substantially.

Do crows get killed by static hazards frequently enough for this to be a good plan? Are they merrily correlating without sufficient eye to causation?


#62

Before us, wouldn’t communicable diseases be the biggie?

There’s no emoji for ‘question with no subtext’.


#63

Same. Also bones that they’ve fished out of someone’s trash. (Probably after the trash pandas scattered it.)


#64

I’m honestly not sure. West Nile virus produced a ton of papers about death from disease; but all rather unhelpful from the “so imagine I was an avian actuary trying to design a maximally useless health insurance plan for crows…” perspective; though, unshockingly, previously unexposed populations went down like wheat before the reaper when West Nile showed up. This one, at least, had the politeness to say what happened to the non-WN cases: “WNV-negative crows (n = 85) died from traumatic injuries (51.8%), predation (16.5%), avian pox (14.1%), pneumonia (11.8%), and poisoning (5.9%).” Non-predation traumatic injuries aren’t further specified; I assume windows are not helpful.

This one is pretty old; but has mortality rates by age and ranges for a number of species, which seemed somewhat relevant; though the ‘band and recover’ approach probably overestimates causes of death that leave a body, uneaten, to be discovered; looks like food stress is a thing for some species, disease/unspecified a major one, and getting shot a major one.

This one on crow inbreeding suggests that infectious disease must be a reasonably significant factor in the absence of getting shot or poisoned; but not clear how many die of disease vs. predators.

Also, if disease is the major risk, that would raise the question of whether association with a given area is helpful(yes if the local food items are coated with soil borne parasites or something; probably not if birds are dying of things with incubation periods that allow them to proceed without incident for some days or more and die pretty much anywhere within their normal range); and whether gathering around to observe the dead might actually be risky(probably not if close contact is required for transmission; possibly if it’s air or mosquito borne).

I will have to look further.

(edit: in the course of looking for crow mortality numbers I ran across this report of a cluster of poisonings in Portland early this year. Probably not terribly noteworthy in itself; but I looked up the ‘Avitrol’ agent believed responsible and its intended mechanism of action seemed to rely on a variant(though one that requires less cognitive sophistication) of this learned-fear behavior.

Our wiki overlords report that 4-Aminopyridine is fairly low toxicity(even has some human medical applications); but that it is a potent convulsant. The theory of using it for bird control is that seeing poisoned birds flailing and seizing and emitting distress calls will freak out the flock and inspire them to not return. From here:

Mode Of Action: Avitrol causes behaviors similar to an epileptic seizure. Birds eating the treated bait will emit distress signals used by their species when they are frightened or injured. This may include flying erratically, vocalizing, trembling, dilation of the pupils and other symptoms. This will frighten the flock and cause it to leave the site.

)


#65

Crow sledding in Russia:

https://youtu.be/3dWw9GLcOeA


#66

The one thing I learned from this is that crows hate performance art


#67

Cowabung-KAW!


#68

Paramedics may not all be serial killers [citation needed], but you’re more likely to avoid danger if you avoid places where you see people with reflective jackets getting together with any frequency.


#69

I am always amused at the lengths humans will go to in order to not empathize with non-human creatures.

“We must posit a reason for this behavior that is unlike the reasons humans do this!”


#70

We had a several large ponds on the campus at my former employer. There was a particular Great Blue heron that would “beg” from people eating their lunches near them at the picnic tables. It would only accept potato chips. Which it did not eat. It would flatly refuse bread crusts. It would take the potato chip and place it atop the water. When, inevitably a brave member of the school of bream would rush out to hit the chip, the heron would strike. If he saw a turtle approaching, he would take his precious chip out of the water and walk away.

I’m not sure where it learned to fish, maybe from people feeding the fish. But it had certainly learned that bread got soggy and sank quickly and was a sub-par bait.


#71

My theory:
Crows all look pretty much alike. So when a crow sees a dead crow, it has talk it over with others of its flock to ask ‘Is that me?’

(By the way, I’ve seen ravens do this too.)


#72

My grandparents (in the rural south) mentioned it. They saw it used by some neighbors as children-it involved shooting a crow and hanging it up on a pole in the garden. The crows would gather, hold the “funeral” and not come back to raid the garden. It sounds harsh, but when crows were destroying your crops it probably seemed an OK solution.


#73

The one complication in this case(clearly solvable by some questionably tasteful research) is that this experiment seems to have involved just ‘dead crow’. Conspecific; but not otherwise related to the live crow subjects.

In order to determine whether the crows are holding a funeral or an inquest the experiment would seem to require comparison of ‘dead crow’, ‘dead crow from test flock’, ‘dead mate of test crow’, ‘dead crow hatchling’; and ‘dead crow hatchling of test pair’.

In humans you’d expect some inquiry and maybe general deploring in the ‘dead human’ case; more in the ‘dead human infant’ case; but much more intense reaction in the ‘dead human from test group(unless he was an asshole who had it coming)’, ‘dead spouse’; and ‘your dead baby’ cases. We’d have a much stronger case that this isn’t just a risk assessment thing if crows, similarly, react more strongly to dead socially salient stimuli(we could even see if ‘crow that died several years ago’ is now less salient than ‘crow that died yesterday’).

If the reaction across the board is a ‘dead guy; probably don’t want to join him’ then that isn’t terribly similar to the human case. If it varies by closeness of relation and time from loss; that seems much more likely.

Now, especially if the latter hypothesis is borne out, it would probably be a bit uncomfortable to go murdering crow families just to see if the response is more intense; the IRB might want something more than idle curiosity unless you could obtain the necessary subjects after their deaths by other causes.


#74

This topic was automatically closed after 5 days. New replies are no longer allowed.