The food source involved in this feeding frenzy has been debated for some time, though intelligent and intrepid birders have come to somewhat of a consensus in that the meal of choice is almost entirely barnacle larvae. A few have collected samples of what the gulls were eating. Last year Charlie Barnard brought samples to our own CAS Conservation Biologist Twan Leenders who took a look at it and passed it on to other scientists. Here are a couple of shots Twan had taken...
There was, as usual, some debate, though our belief is still that these are barnacles in the cyprid stage. Others, including Dennis Varza, Larry Flynn, and John Barclay have done a tremendous amount of work in collecting samples and researching this, coming up with that conclusion. All credit goes to these great birders with inquisitive minds and commendable efforts. If an expert in the field has anything they would like to contribute we would love to hear it.
Photos © Twan Leenders