People on Anglesey have been urged to call a phone line to report sightings of grey squirrels as part of a cull.
Conservation experts want to make Anglesey a haven for red squirrels
A conservation project on the island is looking to increase numbers of red squirrels which are often pushed out by their grey counterparts.
The greys are being humanely culled to boost red numbers which have increased from 40 to 200 over the last 10 years.
Around 8,000 greys have been killed in the last decade. Sightings should be reported to 01248 725700.
Conservationists say there are only around 50 adult greys left on the island and they are hoping those remaining will be eradicated altogether within three years.
Grey squirrels compete for food with reds, damage woodland habitats and can also carry the squirrel pox virus which is deadly to red squirrels.
"The end game is in sight," said Dr Craig Shuttleworth, woodland ecologist with Menter MŰn, the Anglesey Enterprise agency which is leading the conservation project.
"If we can get rid of all the greys, then Anglesey can be a long term island refuge for the red squirrel."
The grey squirrels caught in the traps are killed humanely
Becky Moss, co-ordinator for the Friends of the Anglesey Red Squirrels said more had been released into woodland not far from Menai Bridge and there were plans to reintroduce red squirrels in other areas soon.
The culling project involves up to 400 traps baited with maize being set and checked twice daily in woodlands and gardens across the island.
Grey squirrels caught in the traps are then killed humanely.
The bodies are used for scientific research into the squirrel pox virus.
Dr Shuttleworth said people should also contact them if they saw any red squirrels.
"With the progress we're making, we're hoping it won't be too long before we have 1,000 red squirrels in Anglesey," he said.