Unusually fierce Black-headed Gull fight
I shot the following video recently in a Black-headed Gull colony, showing two Black-headed Gulls involved in a fierce fight.
It caught my attention because the level of aggression displayed is rarely seen in Black-headed Gulls.
Black-headed Gull fights occur frequently during the breeding season, but typically involve displaying various threatening postures, loud calling and charging at each other with little or only brief physical contact.
The video shows a very one-sided fight where one adult has taken hold of another adult and tries to pin him down. The adult on the receiving end seems incapable of responding and is left to endure the whole process.
What’s more, the attacker is seen to make stabbing movements, apparently with the aim to harm the other individual.
Black-headed Gulls (Chroicocephalus ridibundus) fighting, 1 June 2012, Zoetermeer, The Netherlands.
The video is nearly 4 minutes long but I had the feeling that I only saw part of the fight and that it had gone on for quite some time already.
It ends by the victim finally responding and being able to free himself. He is then able to fight back and the fight continues for a little while, after which the victim flees and the attacker decides to leave it at that.
Large gull behavior
I have only observed this type of fighting before in large gulls, particularly Lesser Black-backed Gulls and Herring Gulls. In the 3 seasons that I have observed Black-headed Gulls in this colony, I have never seen this type of behavior before.
This is backed up by finding only few literature references. The only reference I was able to find was in Birds of the Western Palearctic interactive:
Actual fights described as not common and not damaging (Moynihan 1955), or often very violent in contrast to those taking place in air (Manley 1960b): birds try to get on top of each other to deliver downward peck; one may grasp some part of other’s body and much wing-flapping occurs.
I have ordered the referenced document Some aspects of reproductive behavior in the black-headed gull (1955) and related species by Martin Moynihan and will report back when it contains relevant information. (See Rare Rage – Update.)