Why a GULL'S egg??

gnipilbkcaB again.

An ex-Fire-service colleague of mine, after a big meal would always claim that he was ''Full as a gull's egg.''

I was always mystified by the expression for a couple of reasons.

1. I never did find out why a gull's egg should be any more full than anybody else's.
2. I know Gulls used to nest in profusion on a shallow pond 5 miles inland at Aspatria, but Dammit Penrith is 35 miles from Silloth (''On Solway''). WHY did he ever choose a Gull's egg when he's been a landlubber all his life??