Hertfordshire, Middlesex and beyond - the maps!

The project co-ordinators, Liz Goodyear and Andrew Middleton, spend most the season surveying for butterflies in Hertfordshire & Middlesex.

Some of the techniques developed for landscape sampling for White-letter Hairstreak have been based on work that both Liz and Andrew have developed whilst searching for suitable habitat for the Purple Emperor.  More information click here

One of our first principles for finding Purple Emperor is to find suitable habitat and that involved searching for abundant sallows, the larval foodplant. One way to do this is to look for sallows in the spring when the catkins are highly visible in the landscape. This is the exact same principle identified for searching for elm, to look for the flowers and their seeds that also can be seen across the landscape in hedgerows or along wood edges and in particular along road verges. The A505 from Royston to the A11 in Cambridgeshire is an exceptional example, where in spring the elm is highly visible! For most of the year the elm is easily overlooked, which is just the same for sallows

Having found the elm in spring, we returned to as many areas as possible in the summer to find the adults. All sites in Hertfordshire proved positive, and additional sites for both elms or White-letter hairstreaks were found.

The distribution maps for Hertfordshire & Middlesex shows quite clearly the number of 2km squares where the species had been located between 1995 and 2004.

Map 1: 1995 - 1999 White-letter Hairstreak Distribution Ref: Hertfordshire & Middlesex Butterfly & Moth Report 1999 John B. Murray & Rob Souter	Map 2: 2000 - 2004 White-letter Hairstreak Distribution Ref: Hertfordshire & Middlesex Butterfly & Moth Report 2004 John B. Murray & Andrew Wood	Map 3: 2005 - 2009 White-letter Hairstreak Distribution Ref: Hertfordshire & Middlesex Butterfly & Moth Report 2009 John B. Murray & Andrew Wood

Map 1 from the 1999 Branch Report shows that the species was found in only 2 x 2km squares in TL41 and 3 in TQ39. In 2004 (Map 2) this was reduced to one individual in TL41 and 2 x 2km in TQ39 - however these were all different squares.However, the map (Map 4) shown below, generated from our own personnal records in 2005 and 2006, shows a totally different picture in these two 10km squares. In addition to this several other 2km squares have been added.

Map 3 shows the distribution for the period of the project in Hertfordshire and Middlesex and includes many of our records.

Map 4: 2005 - 2006 White-letter Hairstreak Records - Hertfordshire & Middlesex only (Liz Goodyear & Andrew Middleton only) Ref: Liz Goodyear & Andrew Middleton personal records

Furthermore, Liz Goodyear had to travel to Norfolk on several occasions in July 2006 and was able to find several more colonies of White-letter Hairstreak either along the route of the A505/A11 or between Norwich and Horning.  These records are shown in the regional map (Map 4).

Map 4: 2005 - 2006 White-letter Hairstreak Records - Eastern Region (Liz Goodyear & Andrew Middleton only) Ref: Liz Goodyear & Andrew Middleton personal records

Every site in TL41 we targetted as having sufficient elm to maintain a colony proved positive. The two targets in Essex were completed in 2007. In TQ39, only one 2km where elm was present White-letter Hairstreak has proved elusive! The targets in Essex have not been surveyed for elm. In Cambridgeshire and Suffolk all sites proved positive, but there were a few in Norfolk near the end of the season where although a sighting was made, they were of singletons in flight and/or close to oak and Liz has not submitted them to the branch recorder although they are shown on Map 4. Click here for more detailed recording notes

For the story in Yorkshire, read Martin Greenland's notes which include distribution maps of Yorkshire......