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NEYEDC improve and inform environmental decision making, conservation, land management and sustainable development in North and East Yorkshire through the collation, management, analysis and dissemination of biodiversity information.

The Natural History of Yorkshire in 100 Species

Explore the rich and diverse natural history of our region through the stories of 100 species, told by the people who know them best.

#44 Hairy Hawker by Alistair McLean

Meet Alistair McLean, dragonfly recorder and curator of Natural Science at Sheffield Museums Trust!

Alistair McLean is the curator of natural science at Sheffield Museums Trust and the dragonfly recorder for South-West Yorkshire and the Sorby Natural History Society.  Alistair has been fascinated with dragonflies throughout his career. His first experience of fieldwork was assisting with the recording of dragonflies in South Yorkshire and North Derbyshire, as part of his work at Sheffield City Museum. This resulted in the publication of the Dragonflies of the Sheffield Area in 2020, a culmination of over 25 years-worth of recording and data collation by Alistair and co-authors Paul Richards and Derek Whiteley.  Alistair can be contacted via dragonflyrecords@sorby.org.uk.

Hairy Hawker © Derek Whiteley

Alistair’s chosen species is the Hairy Hawker Brachytron pratense. Like many of the other hawker dragonflies (members of the Aeshnidae family), the female is mostly yellow/green while the male is predominantly blue. Both sexes have yellowy green spots and stripes on the thorax. It’s much smaller than other hawkers, and as the name suggests, far hairier. The hairs are particularly noticeable on the thorax, but continue most of the way down the abdomen. The coloured markings are quite muted in comparison with other similar dragonflies, so the overall impression is of a quite dark coloured dragonfly. Combined with the hairs, a quick glimpse in flight can give the impression that it has a dark purple tinge. More can be found out about this species from the British Dragonfly Society or the NBN Atlas.

This is a species that has been, gone away and come back again. Its preference is for clean, slow moving water, and drainage ditches, dykes and fens are often cited as good places to find them. Records from literature sources and museum specimens show that the Hairy Hawker has been present in the UK for at least a century (and probably much longer), and suggest that it was once widespread across the UK. The species was badly affected by changes in farming practises and drainage management during the post war period.  Up until the 1990s, Hairy Hawkers were rarely spotted and restricted to a handful of sites in Yorkshire. Over the last few decades, improvements in land management, and more than likely the effects of climate change, have turned things around for this species. The midlands of England have become its heartland, but its spread across the country has been remarkable. Even so, changes in distribution in Yorkshire have until recently been glacially slow.

Alistair recalls the first records of the Hairy Hawker at Potteric Carr Nature Reserve in Doncaster in the 1990’s: “Since then, each year, we would spend days looking for it spreading further into Yorkshire, but we never found it. Then in the last 5 years or so, it’s like a dam has burst and now it seems to be cropping up everywhere. It’s coming into the Sheffield area from the South and North East simultaneously! The reason for its sudden and dramatic re-colonisation of Yorkshire are unknown. There’s so much we don’t understand, and much of it can only be found out with careful observation and recording in the field. The essence of natural history.”

Treeton Dyke

Overall, the news for the biodiversity of dragonflies in Yorkshire has been good. Driven by general improvements in water quality, warm summers and mild winters, we are seeing species entering (or more likely re-entering) the county at an unprecedented rate. But while warming may introduce new dragonfly species into the area, it could just as easily force others to leave, either as a result of increased competition, or simply as a result of extreme temperatures to which Northern species aren’t adapted.

Recording and monitoring

Continuing monitoring is needed to ensure we keep tabs on things. We can’t protect something if we don’t know it’s there. Dragonflies are monitored through the British Dragonfly Society’s recording scheme and the Yorkshire Dragonfly Group. Sightings can be entered on iRecord, where they’ll be checked and verified by one of the county recorders. Alternatively, records can be sent to your local recorder. Further details can be found here.

Further information and acknowledgements

NEYEDC would like to thank Alistair for his time and expertise in helping to create this blog.

NEYEDC