Although this is obviously a good early spring for gulls in general, this has happened before, in particular for Black-tailed Gull which is probably the most significant 'variable peak count' species.
Black-tailed Gull is a regular early spring migrant in southern and eastern waters as well as winter visitor to Deep Bay, but the numbers reported are usually below 50. However, in some years they can be reported in hundreds, as this chart of peak counts by year from 1980 to 2012 shows
Heuglin's Gull tends to be more consistent, although this may be because most Heuglin's high counts are as winter visitors to Deep Bay rather than spring passage migrants to more remote areas as most Black-tailed Gull high counts are.
So I'm not sure this is a recent phenomenon or just another good year for Black-tailed and Heuglin's.
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Last edited by wgeoff at 11/03/2014 14:35 ]