A WARM sunny start to April boosted butterfly sightings in gardens, the British Trust for Ornithology said.

The BTO, which collects information on garden wildlife as part of its weekly garden birdwatch scheme that runs throughout the year, said the numbers and time of year that butterflies emerge from hibernation was dependent on the weather.

This year, unsettled weather throughout March meant reports of spring butterflies from the 13,000 people involved in the scheme were much lower than in previous years.

But some species of butterflies took advantage of a warm, dry spell at the beginning of April and were much more widely seen in gardens than they were last year, the charity said.

Small tortoiseshell butterflies were seen in almost 40 per cent of gardens, and brimstone butterflies were spotted in a third of gardens - both up from around a quarter of gardens in 2014, and record highs since recording began in 2003.

Peacock butterflies were spotted in more than half of BTO Garden BirdWatch gardens, compared to only a third in April 2014, and another April record for the scheme.

But the good weather did not last, and reports of butterflies dropped off quickly, the BTO said.

Clare Simm from the BTO Garden BirdWatch team said: "As you can see, the BTO Garden BirdWatch is not just about birds. Our volunteers provide us with vital information on other taxa too, helping us to understand how important gardens are as a habitat for all wildlife.

"If this unsettled weather continues, it may be bad news for butterflies so we need to keep an eye on how they fare over the rest of the year."