Warm weather boost for butterflies

01 May 2015 | No. 2015-22

Despite variable weather so far this spring, all it takes is a few days of warm sunshine for butterfly numbers to rocket. The British Trust for Ornithology’s (BTO) Garden BirdWatch results show that this is exactly what happened at the beginning of April, with new records reached for some species.

The numbers and time of year that butterflies emerge from hibernation is dependent on the weather, and this spring was no exception. Unsettled weather throughout March meant that reports of butterflies were much lower than in previous years. However, when a spell of dry, warm weather happened at the beginning of April the butterflies took advantage of it and reports shot through the roof. 

Both Brimstone and Small Tortoiseshell butterflies were reported from about a quarter of BTO Garden BirdWatch gardens at the beginning of April 2014, but this year Small Tortoiseshell was seen in almost 40% of gardens, a record for April, and Brimstone was seen in a third of gardens – the highest proportion of gardens since recording started in 2003.

However Peacock was the biggest surprise seen in over half of BTO Garden BirdWatch gardens compared to only a third in April 2014, and another record for butterfly reports in April. Sadly the good weather did not last, however, and reports of butterflies dropped off quickly.

Clare Simm from the BTO Garden BirdWatch team commented, "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."

Was the short spell of sunshine in April enough for our butterflies, or will the unsettled weather affect their numbers this year? Help us find out!

To find out more about taking part in BTO Garden BirdWatch, including a free enquiry pack and magazine, please get in touch by emailing gbw [at] bto.org, telephoning 01842 750050, write to GBW, BTO, The Nunnery, Thetford, Norfolk, IP24 2PU or visit www.bto.org/gbw.

Notes for Editors

  1. The BTO Garden BirdWatch is the only nationwide survey of garden birds to run weekly throughout the year, providing important information on how birds use gardens, and how this use changes over time. Currently, some 13,000 people take part in the project. The project is funded by participants’ contributions and is the largest year-round survey of garden birds in the world. For more information see www.bto.org/gbw.
  2. The BTO is the UK's leading bird research charity. A growing membership and up to 60,000 volunteer birdwatchers contribute to the BTO's surveys, collecting information that underpins conservation action in the UK. The BTO maintains a staff of 100 at its offices in Thetford, Stirling, Bangor (Wales) and Bangor (Northern Ireland), who analyse and publicise the results of surveys and projects. The BTO's work is funded by BTO supporters, government, trusts, industry and conservation organisations.www.bto.org

Contact Details

Clare Simm
(BTO Garden BirdWatch Development Officer)

Office: 01842 750050
(9am to 5.30pm)
Email: clare.simm [at] bto.org

Paul Stancliffe
(BTO Media Manager)

Office: 01842 750050
(9am to 5.30pm)
Mobile: 07585 440910 (anytime)
Email: press [at] bto.org

Images are available for use alongside this News Release.
Please contact  images [at] bto.org quoting reference 2015-22

The BTO has an ISDN line available for radio interviews.
Please contact us to book an interview
Office: 01842 750050

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