The dark bordered beauty moth. Picture by Roy Leverton

Butterfly Conservation Scotland is leading a survey of the orange tip. New sightings of it have come in from Dingwall, Iona and Mull so far.

The group hopes to improve records of the species, but also gauge the impact warmer weather is having on it.

Meanwhile, there are concerns that unseasonable conditions may harm a rare moth called the dark bordered beauty.

Its eggs hatch to coincide with new leaves on aspen trees.

Tiny caterpillars

Tom Prescott, Highlands and Islands project officer, said there were worries that the hatching and availability of the species' food plant were "out of sync" because of global warming.

Because the dark bordered beauty's caterpillars are so tiny, he said it would not be until the moths were on the wing in June that it would be possible to assess its populations in Scotland.

Reports of orange tips are being sent to the conservation group's headquarters in Stirling.

Mr Prescott said new sightings in Dingwall, Ross-shire, and the islands of Iona and Mull were due to a lack of previous recording work, or the species benefiting from warmer weather.