Ashley Whitlock
Hampshire & IOW Butterflies and Moths
Regional Action Plan for the Purple Emperor
A map of the Hampshire and Isle of Wight shows where all the significant areas are where the Purple Emperor can be found. The heavy concentrations of yellow dots shows the main areas with a few sporadic sightings in the New Forest, like the Duke of Burgundy the New Forest and the Isle of Wight need some good management of areas where these two species could possibly make a come back or as a introduction. The light orange colour on the Hampshire map shows the main area of Purple Emperor sightings and the darker patch is possibly where the specie could have corridors where the butterfly can link up with small areas of woodland, especially over the border with Sussex. Although the area below this is probably a more likely area where the butterfly can be found judging by the yellow dot concentration the human population density in this area requires more housing, roads and other schemes which would not allow for a concentration of small areas of woodland link up.
Most recorders only manage to see the male Purple Emperor in ones or twos in an average year at peak time in many of the woods in Hampshire.
Crab Wood in the Farley Mount Complex west of Winchester is a good place to see the Purple Emperor with good stands of mature Oak and good vistas to see their behaviour.
The female Purple Emperor is a shy and elusive creature, and shuns any sort of interaction with humans if it can. When it cannot then the encounter can be quite spectacular. The species can often be seen searching in and around mature sallow stands in late mornings and into the early part of the afternoon. They are usually seen at rest,and then flying into the back of the sallow and laying eggs, and then appearing again to take a rest before commencing with their task of egg-laying.
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As I've mentioned before in my section on Purple Emperor assembly points to find one of these can give you spectacular views of the Purple Emperor males behaviour in the afternoons, and to find these areas is normally to find the highest point in a wood and stay in that area for at least an hour in good conditions. You may be rewarded, but there are a lot of woods which have no obvious Assembly Point like those on flat ground, which is probably most of the woodland in Hampshire.
Conifer stands are not the most obvious Assembly point trees, but these in the picture are, found in Alice Holt Forest. In fact most of the Assembly areas are conifer in this woodland.
Good areas of sallow in woodland are essential to maintain a viable population of the Purple Emperor. A good place to look for the species and its food plant are 'wayleaves' where there are Electricity pylons going through a woodland. This generally enables the sallow to take a hold and can generate good areas of the foodplant, like here in Creech Wood. This is also a good area to look for the butterfly as it gives good vistas away from high areas of trees which can obscure your viewing of this species, as they often are Sallow searching and Oak edging in the mornings.
West Wood right next door to Crab Wood has good areas to view the Purple Emperor especially over the Oak stands where they can be seen on Oak patrol. They quite often alight on to the ground to imbibe on mineral salts in the late mornings.
Conservation Requirements for the Purple Emperor
Distribution and Status:
Hampshire is a stronghold for the species with adjoining counties with good populations as well, Wiltshire, Surrey and Sussex with small populations in Dorset, and Berkshire. The species has been found on the Isle of Wight in Briddesfield Copse and Parkhurst Forest in the last four decades, but it is only recorded sporadically.
No noticeable change in its range of this species over recent decades, although there is certainly more records coming in for the last few years, especially in good years.
Hampshire 1995-1999 = 29 tetrads
Butterfly Conservation status: High
Number of 2020 records - 53
Number of 2020 individuals - 140
Number of tetrads: 29
Number of post 2005 tetrads: 192
Threats: Fragmentation of major woodland complexes (smaller and more isolated nature of remaining woodland habitat)
Clearance of sallow from woodland rides
Collectors: Alice Holt Forest has had a major problem over the last few years.
Survey: regular recording in Hampshire throughout 1990’s has confirmed the presence of the Purple Emperor in many woodlands/forests throughout the county but mainly in low density populations. Visits to some of the best woodland complexes rarely record more than a few individuals, and on most visits even experienced recorders struggle to see more than one or two Purple Emperors and very often don’t see any.
The cumulative Purple Emperor tally for a given year from all 130+ regular contributors annual Hampshire and Isle of Wight Butterfly report rarely exceeds 25?
Monitoring: Major woodland sites are surveyed on an annual basis but there are many smaller woods and those on private estates that are seldom visited.
Management: Goat Willow Salix Caprea is the most favoured larval foodplant, although Grey Willow S. Caprea is also used. Sallow management is therefore critical for the long term success of the Purple Emperor colonies. Ideally a varied sallow age structure should be maintained and the ‘master trees’ (usually Oak spp.) used in territorial males should be retained (Willmott 1994) In the past many woodland complexes had their ride side sallow cut and removed because of interference with forest operations and access. However sallow of mixed age and a variety of settings in broad rides are of vital importance for the Purple Emperor. By developing box- junctions and embayment’s along major rides of larger woodland complexes, and even strategic planting of sallow, it should be possible to retain sallow in a range of appropriate settings without causing problems from forestry operations. (e.g Straits Inclosure)
Actions and targets: Ensure that there is no further fragmentation of major woodland complexes where the species breeds.
Create appropriate habitat conditions in the New Forest to enable the species to become more firmly established in the area once again.
Targets: Resurvey all woods in its known range in order to evaluate core breeding areas and extent of metapopulations.
Advise land owners and site managers of the importance or retaining sallow or varying age and position within woodlands.
Introduce sallow into selection of major woodland complexes in the New Forest where the Purple Emperor formally occurred
For all known sites identify favoured sallow, master trees, congregating areas, and inform landowners and land managers.
Not only have ride side sallows got to be kept and maintained other trees like Hazel are useful to the species as in some very hot summers the butterfly tends to 'conk' out early in the morning, and takes up refuge in the hazel stands. This male was doing just that after a very hot foray on to the ride floor, and stayed here in the shade for a good part of an hour, taking sap from the hazel leaves.