The birds, which would not normally be expected at the site for several weeks, are only providing fleeting glimpses, however.

Site manager Ian Kendall said: “It almost feels as though they are playing a game with us, but the truth is they probably leave the cliffs as the weather changes.

“When it gets round to the breeding season proper they’ll stay exactly where they are, looking after their chicks whatever the weather.”

He said it was unclear what had brought the early return, whether it was food availability or changes in the weather, but it made for a great wildlife spectacle.

Up to 60,000 adult guillemots and their chicks can be seen along the chalk cliffs in spring and summer.

l Last year it was announced the site is to be upgraded to become the national seabird centre for England.

The RSPB is to spend more than £1million over the next five years developing the reserve, which already attracts 45,000 visitors a year.

New features will include catering facilities and space for exhibitions and events.

More jobs will also be created at the reserve, which is run by five full-time staff and 40 volunteers.