While observing gulls on one of the beaches at the isle of Terschelling (one of the Frisian islands in the far north of the Netherlands) with fellow (gull) friend Jacob on November 7, we witnessed some interesting behavior between an adult Herring Gull Larus argentatus and an adult Lesser Black-backed Gull Larus fuscus graellsii.
They displayed clear pair-bonding behavior, something which is pretty rare to see outside of the breeding season and even more so when it involves gulls of different species.
In the following video (shot mostly through a car window), both gulls can be seen walking parallel to each other at great pace while performing the mew-call. The Herring Gull is the most vocal of the two and initially we thought that it was the male and taking the lead. Having watched the video several times now I am not sure if it is actually the female and is following the Lesser Black-backed. I also find it difficult to see any differences in size (the larger one would be the male).
The Herring Gull can be seen pecking at objects on the ground and initiating choking-behavior: all clear indications of pair-bonding behavior, possibly even of a pair that is confirming their bond rather than establishing it for the first time.
The scene immediately reminded me of similar behavior that Jan Zorgdrager and I observed between 2 adult Lesser Black-backed Gulls in July 2012 and August 2014, both involving the same individual ringed as Yellow H.501. See one of the scenes here:
See also these previous blog posts: Do adult Lesser Black-backed Gulls pair up in August? and Pair-bonding behavior during post-breeding season by adult Lesser Black-backed Gull Yellow H.501.
To my knowledge, not much is known about adult gulls pairing up during the winter time which makes the observation at Terschelling in the month of November even more interesting.