Dragonflies embody the spirit of summer – these big, beautiful insects are some of the showiest to be found in the UK and watching them patrol along the water is a seasonal delight to be savoured every year. 

Damselflies, the wafting relative of the dragonfly, flutter delicately around the water margins, in counterpoint to the direct, rapid flight of dragonflies. 

Where dragonflies are robust and speedy, damselflies are small and weak-flying. Since dragonflies are formidable and opportunistic aerial predators, damselflies often fall prey to them, alongside all manner of insects, from midges and mosquitoes to butterflies and moths. 

Typically, dragonflies eat on the wing, discarding inedible wings and chitin as they go. If you find a scattering of these parts across a path, it’s a good sign that you’re in a dragonfly hunting territory.

From the earliest emergences in April to the final flights at the end of September, BBOWT conducts dragonfly surveys to monitor populations at our nature reserves. By gathering this data, we can ensure that our habitat management is effective and that populations of some of the region’s rarest species will continue to thrive.

Dragonfly transects are surveyed once a week from the end of April to the end of September. In order to ensure that the records can be compared between years, the methodology and transect routes must be consistent.

I cover two transects in the beautiful Cothill village, at Dry Sandford Pit (shown in the photograph above) and Parsonage Moor (below). One of the perks of dragonfly surveys is that the weather must be warm and dry – any sign of rain or high winds, and dragonflies will seek shelter in vegetation, making them nearly impossible to spot. For this reason, it is a requirement that there should be at least 50% sunshine, and a temperature above 17°C. If the weather isn’t good enough, the survey can’t go ahead.

Dragonflies primarily hunt over fresh water, so the transect routes go through streams, fen, and reedbeds. This means wading through dense moss in wellies (like below), whilst juggling binoculars, record sheets, and a field guide, not to mention the challenge of identifying the species as they whizz past!

Identification of dragonfly species can be challenging – on sunny days, they appear supercharged and rarely stop to rest. Even if one possesses the patience to track a dragonfly until it lands, their near-360-degree field of vision often scuppers even the sneakiest surveyor’s attempts to view them up-close. 

Further muddying the waters is the fact that dragonflies’ colours and markings can vary considerably. Often, we must rely on General Impression of Size and Shape (jizz). Take the Southern Hawker (first photo below) and Hairy Hawker (second photo below):

Whilst they are clearly distinct in static images, these species can appear as little more than a blue-green blur when travelling at speed. From mid-June to early July, both will be on the wing and observing size and shape will be crucial. 

Before surveying, it is worth taking the time to study their silhouettes and observe their differing size and abdominal position. Quirks of behaviour can also set species apart – the Southern Hawker tends to approach humans, appearing to inspect them before returning to its patrol, whilst the Hairy Hawker tends to avoid humans if disturbed.

When dragonflies are zipping around, it can be difficult to discern their distinguishing features, but by having a sense of size and shape, a surveyor can confidently record even the speediest creatures. When it comes to damselflies, a different approach is required. 

Whilst damselflies are far slower, they’re also often of similar size and overall colour, and their markings are so small that they need to be viewed up close to distinguish them. This can be achieved either by viewing through binoculars, or (if licensed!) catching them in a net.

The two most prolific damselflies at the Cothill sites are the Southern Damselfly (first photo above) and the Azure Damselfly (second photo above) with the star species being the rare and threatened Southern Damselfly. On the second abdominal segment, just below the wings, it bears the mark of mercury ☿ which separates it from the Azure Damselfly. Their jizz is also distinctive – the Southern is a dainty, weak flier, whist the Azure appears stronger and more direct. 

Whilst these species initially appear similar, many differences become apparent upon closer inspection, and with some experience they can be readily distinguished.

Accurate recording of the Southern Damselfly has been instrumental in informing BBOWT’s management work, which has produced great results for the species over time.

Whilst average sightings at Dry Sandford Pit decreased from their record highs in 2007, they have recovered and begun to appear in greater numbers once more. Crucially, they have also expanded their range and now maintain a consistent presence at nearby Parsonage Moor.

This is excellent news for the species, since having multiple populations in close proximity makes them more resilient to any setbacks that might befall a site. 

With diligent monitoring and thoughtful management of the sites, Southern Damselflies will be set to thrive in Cothill for many years to come.
The success of the Southern Damselflies at Cothill is in line with the national trends for many other dragonfly species – since they enjoy warmer climates with more insect prey, many species previously only recorded as European vagrants have begun expanding their range into the UK.

One such species is the Norfolk Hawker, which was recorded this May as an exciting county-first at College Lake by the Buckinghamshire Invertebrate Group.

This newcomer highlights the fact that our climate is changing. Its presence is somewhat bittersweet, as it is a species that will benefit as many others will suffer. Unusual and exotic species will be spotted more frequently in the coming years as the climatic envelope shifts, bringing new ID challenges. 

Whilst these appearances are exciting, they also serve as a tangible reminder of the importance of our conservation work – the changes that we are experiencing will be too great of a challenge for many species to endure without our support. 

Dragonfly surveys, along with all other aspects of the Reserve Surveying Programme, are an essential component of BBOWT’s work, and enable us to do the best we can for the species that need us the most. Many of the surveys are carried out by BBOWT's volunteers and we are very grateful for their invaluable contribution to our knowledge of wildlife across our three counties.