The common cormorant (or shag)

Lays eggs inside a paper bag,
You follow the idea, no doubt?
It is to keep the lightning out.

But what these unobservant birds
Have never thought of, is that herds
Of wandering bears might come with buns
And steal the bags to hold the crumbs

Christopher Isherwood [wikipedia on Cormorants]

The last couple of days a whole flock of cormorants (at least I am reasonably sure that is what they are) have taken up residence on a set of pilings between Wandsworth and Battersea bridges. Makes a change from the common gull.

And they set off memories of this poem.