Are Dorset Chalkhills endangered?

Front view of Chalkhill Blue
Chalkhill Blue. Photo: Mel Bray

We are concerned about Chalkhill Blue numbers in Dorset, which seem to be plummeting for reasons we do not know.

While the number of kilometre squares in which they were recorded between 1970 and 1994 was 197, the comparable figure for 2010-14 was 59; even compared with another five year period (1995-99) it has dropped from 88 to 36.

Table showing Chalkhill numbers

There is always a chance, though, that the problem is under-reporting rather than a real lack of butterflies, so we need places where they have been seen before to be visited. The first Chalkhill Blue in Dorset for 2018 has just been reported, so they are coming out, and likely to be around for the next 4-6 weeks or possibly a bit longer.

To find out where to look please click below:

The above are all PDF files to ensure you can open them, but we can supply the original MS Excel file with multiple tabs and including maps showing the kilometre squares in which the butterfly has been sited in each given time period – please contact us via our Enquiry Form if you want this.

The places listed have not been checked for legal public access. Please ensure you only use roads or public rights of way unless you have the permission of the landowner.

It is advisable, if you are able, to visit the site several times during the flight period, to give you the best chance of finding the butterfly. Some help with identification can be found on our species page .

If you do search any of the locations listed, please record your sightings via this website’s recording page. IF YOU SEARCH AND DO NOT FIND ANY CHALKHILLS, IT IS VERY IMPORTANT THAT YOU LET US KNOW – PLEASE TELL BILL SHREEVES BY EMAIL (w.shreeves@btinternet.com) INCLUDING THE GRID REF AND DATE YOU SEARCHED.  A photo of the butterfly(ies) to help with verification would be helpful – send them in to our gallery page – but this is not essential.

A chalky blue butterfly on a yellow flower

Chalkhill Blue. Photo: John Woodruff.

Thank you very much for your help.

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