RSPB members have been protecting the birds

The theft is the first on Mull since police, along with the Royal Society for Protection of Birds, began Operation Easter aimed at deterring egg thieves.

Richard Evans, of the RSPB, said: "We had a close look at the nest. It has obviously been climbed and there is no sign of the eggs."

Undercover wildlife liaison officers from Strathclyde Police Force have set up observation points on the island.

Farmer Donald MacGillivery said: "We're devastated by it. We really feel we are the custodians of those birds.

"Egg thieves coming onto our island are taking from us what we really feel is part of our heritage.

"I don't love sea eagles, but I certainly don't love egg thieves."

Of the thieves, Dave Dick of the RSPB said: "People should not approach these guys because some of them have got previous convictions for violence.

"They are very, very unpleasant people. They are criminals."

There is one other pair of breeding sea eagles on the island and the hope is that, with RSPB and police protection, they can be allowed to rear their chicks without being attacked.