EGGS of a rare protected seabird nesting in Poole Harbour have been stolen - and experts believe they may have been mistakenly swiped and sold to top restaurants.

To non-experts, the Mediterranean Gull eggs that have been taken look almost identical to Black-headed Gull eggs, which can be legally harvested under licence for sale to the gourmet food industry.

However, there are only 18 people in the south of Britain licensed to collect Black-headed Gull eggs, which can sell for around £7 each.

The Mediterranean Gull eggs - which may not even be safe for human consumption - are protected under law. Unlicensed collection of Black-headed Gull eggs is also illegal, and the collection of either species' eggs in Poole Harbour is strictly prohibited.

The discovery of the egg thefts, which could net criminals thousands of pounds, was made by the Birds of Poole Harbour charity when it carried out a survey of the 'Gull Islands' in Poole Harbour earlier this month.

Paul Morton, from the charity, explained: "The issue is that both Black-headed Gulls and Mediterranean Gulls look very similar, and their eggs even more so.

"So when an illegal egger goes out to the islands in the dead of night to harvest the eggs, the nest of the two species are so tightly packed next to one another that there is absolutely no way of knowing which eggs are being swiped.

"Also, restaurants will have no idea that they may be selling the eggs of a schedule 1 species, putting them at risk of prosecution."

Schedule 1 species of seabird are specially protected under the Wildlife & Countryside Act 1981. It is an offence to interfere with their nests or eggs.

During the Birds of Poole Harbour survey, the team noted a large number of human footprints and high quantity of empty nests on the islands, which have historically held up to 9,000 pairs of Black-headed Gull, and more recently, 100 pairs of Mediterranean Gull.

Mr Morton added: "There are several causes of alarm here. Firstly, there is absolutely no licensed egging in Poole Harbour, meaning it is highly illegal to take either Black-headed Gull or Mediterranean Gull eggs from the islands.

"Secondly, although the selling and eating of Black-headed Gull eggs is well known, there has been zero testing done on Mediterranean Gull eggs from here in the UK to see whether they are safe for human consumption.

"My advice to any restaurant currently selling gull eggs is to ask their supplier if they're 100 per cent sure of the origin of their eggs and secondly, be very sure you have no Mediterranean Gull eggs in your possession as this could lead to legal proceedings."