I see that the Ian Campbell group lists the author as "unknown" and I haven't had much luck searching thru google.
Ive been singing this and the folks keep asking if it couldn't get longer.
So here's my tentative contribution; criticism and more additions both welcome.

From break of dawn to close of day
The gulls they tuck it all away
And swoop and whoop and loop and play
the gulls of Invergordon
But you had best stay out of sight
Unless you want a coat of white
For loaded gulls still aim quite right,
The gulls of Invergordon.

Blessings
Barbara