Seabird breeding has been "terrible" in some northerly areas such as Orkney and Shetland, RSPB Scotland has warned.
The 700 Arctic terns present at the start of the breeding season on the Shetland island of Mousa failed to produce a single chick.
The organisation said the situation was "similarly miserable" on Orkney.
The RSPB's Doug Gilbert said: "The terrible season for critical colonies in the far north warns us that seabird populations remain in real danger."
Just two kittiwakes were said to have returned to Orkney's North Hill reserve to breed, and not a single chick fledged there.
However RSPB Scotland said some species continued to do well, such as gannets.
The organisation added that research showed seabirds were valuable to rural economies due to related tourism.