I came across this peculiar scene today of an adult Lesser Black-backed Gull Larus fuscus and a second-calendar year European Herring Gull Larus argentatus displaying pair-bonding behavior (walking parallel to each other, mew-calling and choking).
This is strange because not only is the Herring Gull way too young to be pairing up with a mate and to be displaying this type of behavior, but they are not even the same species (although interbreeding does occur).
It will be difficult to explain what is going on here without much speculation.
From the adult’s perspective, I wonder what its incentive is? Is it a case of mistaken identity? It is not until a juvenile Lesser Black-backed Gull comes begging that it seems to realize its error and immediately starts displaying aggressive behavior towards the Herring Gull by long-calling and charging at it.
From the sub-adult’s perspective: what is it trying to get out of it? I was very surprised to see a gull of this age behave and react towards an adult this way and I wouldn’t have thought that it had this type of behavior in its repertoire.
Any thoughts and references to similar observations are welcome.