Carrion Crows mobbing a Heron...

[Ringo1968]

Is that unusual? I saw a couple of crows mobbing a Heron as if it was a Red Kite or another BOP as it flew by,probably en route for some fishing.

[Dogghound]

Very common they are often seen mobbing herons.

[Gill Catton]

Yes quite common. Though I have seen a heronry within a rookery before now so it can't bother them too much!!

Theories vary as to why - an adult heron could in theory eat crow young so could be considered a threat, herons often carry largely undigested food in their crop when on their way back to the chicks and maybe the crows are after this, or some suggest that crows mistake the silhouette of a flying heron for a bird of prey (though I find the last one hard to believe as crows have good eyesight are far from stupid!).

[witham]

crows do tend to be bullies at times we've seen some attacking an owl as it flew along hunting, it could have invaded their 'space' though