22 June 2016
A hunt to find a mysterious and rare seabird is set to start off the coast of Pembrokeshire.
Conservationists will search Skokholm and Skomer islands for the storm petrel - the UK's smallest seabird.
They hope to complete a census of the "Quarry" on Skokholm, which is the largest breeding colony in England and Wales.
Warden Richard Brown said the work would be "challenging" and required "careful planning".
The project forms part of the national seabird census.
Storm petrels are notoriously difficult to count but it is thought about 5,000 of the birds breed on Skokholm Island - up to 20% of Europe's breeding population - and a few hundred on Skomer.
Vicky Taylor, who is volunteering to count the birds, said: "We play the sound of a singing storm petrel to a likely nest site and if there's a bird in there it often calls back.
"It's supposed to sound like a fairy being sick but I think it's more like a purring cat with the hiccups."
The distinctive "musty, oily" smell of storm petrels can also reveal a nest, she said.
The project is being carried out by the Wildlife Trust of South and West Wales and the University of Gloucestershire, with funding and support from Natural Resources Wales.