Stoat: A heron mobbed by crows

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A heron mobbed by crows

Category: misc
Posted on: May 17, 2008 4:51 AM, by William M. Connolley

Cycling back from town yesterday, I saw: in a chestnut tree of moderate height in the middle of an open field miles from the river, a heron. And three crows flying at it, "dive bombing" it is tempting to say although their flight was mostly level. They were trying to drive it away, I suppose, and the heron kept turning to face them, but as far as I could see they never touched it. After perhaps 5 minutes they gave up. And a minute later the heron flew off.

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Comments

I've seen this in Canada with red shouldered blackbirds substituted for crows.

I've also seen in with red shouldered blackbirds vs.crows/ravens.

And all sorts of stuff vs. hawks.

Mating season?

Posted by: bigcitylib@hotmail.com | May 18, 2008 8:08 PM

Crows will even mob sea eagles if necessary. It (usually?) indicates the presence of nearby nests. I'm sure you knew that.

Posted by: Adam | May 19, 2008 7:17 AM

I believe that the explanations given are incorrect.

Crows are very smart. They apparently watch herons feeding and mob herons who have recently eaten. Herons in such a state are loaded-down and cannot fly well. When mobbed, the heron will often disgorge its meal enabling it to escape, while the crows get an easy meal.
The explanation came from an old friend who was once nearly hit by a fish that fell out of the sky. He seemed to think that mobbing of herons by crows was not unusual.

Posted by: ScaredAmoeba | May 19, 2008 9:18 AM

That's an interesting idea and certainly believable. I do know that crows will attack predatory birds to protect nests, but I suppose it's moot whether the heron would be considered by the crows to be a threat.

Posted by: Adam | May 19, 2008 9:51 AM

It's clearly a function of size vs. fear of predation. This morning I was walking my dawg through the local cemetary when I heard a right old kerfuffle kicking off.

A murmuration of starlings weren't so much murmuring as screaming their little beaks off at the sight of a crow hopping around amongst the gravestones.

By the time I got nearer the crow had dutifully despatched one of the tiddlers, flown up on top of the chapel and was efficiently scoffing its innards. Clearly too late for life saving intervention the other starlings cleared off in silence.

There's also the photo on the Beeb news page somewhere of a nesting box that someone has had to reinforce with steel plate in order to stop a woodpecker making off with blue-tit fledglings...red in tooth and claw and all that!

Imagining that herons invoke similar responses in crows is somewhat of a consolation.

Posted by: Hugh | May 19, 2008 11:03 AM

"There's also the photo on the Beeb news page somewhere of a nesting box that someone has had to reinforce with steel plate in order to stop a woodpecker making off with blue-tit fledglings...red in tooth and claw and all that!"

Blue tit nesting boxes are generally best reinforced around the entrance hole to stop squirrels, who are rather partial to eggs. Was it a (greater) spotted or a green woodpecker?

Posted by: Adam | May 19, 2008 12:15 PM

Here ya go (GS I'd say):

http://news.bbc.co.uk/1/shared/spl/hi/pop_ups/08/uk_enl_1211108101/html/1.stm

Plus...on another note, I could also suggest that the whole thing could be regarded as a analogy for the persistant social myth that crowds panic on being confronted by a hazard. Whilst copious evidence suggests that crowds actually behave very rationally during 'emergency situations' sometimes running around flayling your arms about and shouting warnings to others is actually the most practical thing that you can do (notwithstanding that these tactics probably wouldn't work if the 'hazard' looked anything at all like a Grizzly Bear...but then, I don't think they like crowds much!!).

Posted by: Hugh | May 19, 2008 12:29 PM

My favorite bird-v.-bird sighting was five magpies against one kestrel, in Alaska. Seemed like a pretty even match-up of attack helicopters against a fighter jet, but we had to leave before the end.

Posted by: Brian Schmidt | May 19, 2008 3:45 PM

"Here ya go (GS I'd say):"

Thanks for that! And yes, I agree.

Do you suppose running around flayling your arms would cope with the threat of sea level rise? ;) I suppose it could if you flayled in a vaguely swimming stylee...

Posted by: Adam | May 19, 2008 4:49 PM

Hmmm... that's a strangely pertinent question Adam.

From my work I would suggest that when incremental SLR does first reveal itself in the shock of an extreme surge event that overtops or breaches sea defences(1953 style), the response will predominantly be one of complete disbelief.

In the UK there has been a significant increase in 'planning' for such long-lead time (circa 24hrs)events in recent years; an example being last November's surge which fortuitously reduced in magnitude prior to its arrival at Great Yarmouth (where incidently sections of the defences are down to 1:40 year)

However, people have an unerring capacity to learn by trail and error and, unfortunately, if all your experience suggests that the event you are preparing for *isn't* going to happen then you tend to prepare accordingly (it's why I always suggest that people call them 'near misses' instead of 'false alarms')

It's an awareness vs. preparedness issue really. The trick will increasingly be to normalise flood risk and household/street scale emergency planning...something which should be timetabled into school curricula (remember Tilly Smith saving all those lives in Phuket during the tsunami?).

One of my sample towns is served by two main roads only one of which runs perpendicular to the shore and out of the flood zone, it also has a significant percentage of retired or long-term ill within its population...living in bungalows!!

You've raised a thorny issue!

Posted by: Hugh | May 19, 2008 5:52 PM

"You've raised a thorny issue!"

Hmmm,...many a word spoken in jest.

Actually I think it's highly likely that people will realise that the sea defences are probably not adequate, just after the point they get over-topped. And even if it took 100 years or a 1000 years, they'll start to adapt to a new level just about the time it reaches that level.

Posted by: Adam | May 20, 2008 9:56 AM

He seemed to think that mobbing of herons by crows was not unusual.

Not unusual at all. What is unusual is seeing the two species in the same area without the crows mobbing the heron.

Posted by: Dunc | May 21, 2008 8:44 AM

I've also seen crows harassing herons, and it wouldn't surprise me at all to find they have learned to do so because of the possibility of the heron disgorging a recent meal. I once saw several crows harassing an eagle which was carrying some kind of prey in its talons, which it eventually dropped. The crows went straight to ground after the dropped prey, while the eagle flew off.

Posted by: Bee | May 22, 2008 11:46 AM

Hmmm...
It would appear that this would explain it:
http://www.guardian.co.uk/environment/gallery/2008/jun/26/wildlife.ireland?picture=335287431

Posted by: Hugh | June 26, 2008 5:11 PM