Caspian Gull at Minsmere: John Grant

John Grant

Caspian Gull (Larus cachinnans) is now firmly on many Suffolk observers’ ‘radar’, having progressed from originally being a poorly-known race of Herring Gull (L. argentatus) to official recognition as a full species in 2008. Suffolk Birds continues to refer to it as a “scarce visitor” but many observers are becoming increasingly familiar with the species’ key identification points and, indeed, appreciative of its unique character and beauty.

With its often-sizeable gatherings of large gulls, the Scrape at RSPB Minsmere is one of the best locations in the county - or country - to observe ‘Caspos’ and I have had the pleasure of seeing and enjoying many there in recent years. Even so, I was somewhat surprised to see what I took to be a fourth-calendar-year male ( an individual that retained a few brownish markings in its tertials and exhibited a few fine grey-brown streaks as a ‘shawl’ around its lower nape) in full display mode on Minsmere’s West Scrape at about 18.15hrs on April 15th, 2019.

Viewing from the reserve’s Wildlife Lookout Hide, I noted the bird on a small grassy island about 75 metres away and was immediately struck by its behaviour towards a similarly-aged Yellow-legged Gull (L. michahellis).

The Caspian Gull strutted around the Yellow-legged Gull with its long neck fully extended upwards in a rather haughty ‘giraffe’ pose, its long, thin bill pointing directly upwards as the bird circled its more-demure ‘dance partner’ on many occasions. All the while, the Yellow-legged Gull, which I took to be a female, adopted a submissive, stationary, crouched and flat-backed posture with ‘her’ head outstretched and ‘her’ rear end frequently raised. The Caspian Gull continued to circle the Yellow-legged Gull, breaking off, occasionally to lunge at any Herring Gull that wandered too close. These lunges seemed particularly aggressive and were carried out with both wings held out widely at about 90 degrees to the body, in ‘albatross’ pose. The bird would run towards an interloper and the bill would be jabbed towards the unwanted intruder.

I had never seen such behaviour among either species before so I tried to film it with my mobile phone attached to my telescope. However, infuriatingly, but absolutely typically for me, the phone ‘died’ as soon as I tried to begin! I continued to watch the display, which went on for a total of at least 15 minutes, until the Caspian Gull suddenly took flight high to the south. The Yellow-legged Gull remained on the grassy island, in more conventional pose, for at least another 30 minutes, at which time I left the hide.

I am aware that Caspian Gull often hybridises with other species in some European countries - indeed, we sometimes see indeterminate gulls in Suffolk that apparently have mixed parentage and are the cause of much wrangling over identity - and I was left to contemplate that one day this fascinating species might begin to do so in our county. That would pose even more interesting identification questions, no doubt!