February 16th saw attendance at the evening roost at Tophill Low NR, East Yorkshire for the 90th time this winter since returning from Portugal on November 12th. This is probably the first time the winter gull roost has been checked nightly since D reservoir was created – only six nights have been missed over the winter period.
To date 11 species have been noted during this campaign and while it is impossible to determine the total number of birds using D reservoir each winter, it is possible to determine by and large, the total number of certain species.
Mediterranean Gull Ichthyaetus melanocephalus is one of those species, and individuals change quite regularly, indicating that both Common Gull Larus canus and Black-headeded Gull Chroicocephalus ridibundus move through the roost in incredible numbers between October and late March – the usual gull roosting period.
First-winter birds have so far proved to be the commonest age type seen over the winter, with a total of 17-21 individuals – these birds photographed in February 2016 and November 2015.
A total of 13-14 2nd winter birds have been seen – these photographed in February this year and December 2015.
Adult birds have been noticeable by their absence with very few being seen in 2016 so far, but still 12-13 have been noted over the winter period as a whole – these two both appearing in December 2015.
These numbers give a running total of 42-48 individual Mediterranean Gull I. melanocephalus over the 90-day period.
Back in April 2014, I suggested, based on notes and photographs, that over the course of the previous winter period 2013/14, 31-38 birds appeared in the roost, but perhaps as many as 50+ wasn’t out of the realms of possibility. However, this was based on observations only taking place two nights a week over the period and the number of roosting gulls was higher during that period than the poor totals noted so far in 2015/16 – numbers of Common Gull L. canus and Black-headed Gull C. ridibundus have rarely reached a combined total of 10,000+ birds during what has been a mild winter.
So how many more will appear in what is left of the gull roosting season? And what else will drop in?