Puffin chicks on a group of remote Scottish islands are starving to death, according to the National Trust for Scotland (NTS).
Dead chicks next to a glove provided for scale
Adults are not finding enough food in the sea around St Kilda, which has left their young "severely malnourished".
The trust, which owns the archipelago, said the numbers of eggs hatching were also down.
Last month, RSPB Scotland said Scotland's seabirds were having a "disastrous" breeding season.
Sarah Money, the NTS seabird ranger on the islands, said puffins were struggling to find their normal food of nutritious and oil rich sand eels, young herring or sprats.
She said: "The chicks are just dying of starvation, with hundreds of emaciated bodies lying around outside the burrows.
"Since July, the parents have been bringing back mainly pipefish, which the chicks can't swallow. Many of the burrows contain piles of uneaten, rotting pipefish."
She added: "Before 2001, snake pipefish were rarely seen in Scottish waters but have been becoming increasingly common in recent years.
"It is feared that this is another symptom of climate change as they are a southern species that have been extending their range northwards."
However, guillemots have done "reasonably well" on St Kilda.
Rangers on the Hebridean island of Canna and St Abbs Head in the Borders, which are also owned and managed by NTS, have also reported an increase in pipefish.
Bob Swann, who has been studying the seabirds on Canna for more than 30 years, said: "We have never seen this before.
"The kittiwake parents have been bringing pipefish back for their chicks which have been dying in large numbers."
St Abbs Head ranger Kevin Rideout said they were seeing one chick raised for every eight nests.