Electric fences protecting the site on the Norfolk coast were ripped out of the ground, nests wrecked and eggs smashed in the overnight attack.
The rampage sent the little terns, among the UK's rarest breeding sea birds, scattering at the height of the breeding season.
They are not expected to return to the colony on Great Yarmouth's North Denes beach this year.
Malicious attack
Two thirds of the 90 nests have been destroyed in the attack which a spokesman for the Royal Society for the Protection of Birds (RSPB) said must have been malicious.
As the vandals struck, more than 300 little terns took flight, leaving about 25 birds on the ground.
Some have since returned, but others have completely disappeared.
RSPB Broads manager Ian Robinson said it was definitely a deliberate act.
"The whole section of the Denes there, owned by Great Yarmouth Borough Council, is designated a protected area based on the fact that little terns are there."
Each year about 220 breeding pairs arrive at the colony to raise their young.
"As they are the second rarest breeding sea birds in the country, we do our best to protect them from land predators and people to try to provide conditions to maintain the population of the birds in this country."