A Green Snaketail turns up over the mining-shaped Bolina valley

A Green Snaketail (*Ophiogomphus cecilia*) was recorded twice on August 27 in the Bolina valley in Katowice, the two sightings a few hundred metres apart on the stretch of stream and old mine ponds between Giszowiec and Janów-Nikiszowiec.¹ It is a dragonfly of sandy lowland rivers, and the ground it was seen over is about as far from that as Upper Silesia gets.

The adult is hard to mistake once seen well. It is a large dragonfly, 50 to 60 millimetres long, with an apple-green face, green eyes and a green thorax marked with thin black lines.² The abdomen is black with a broken run of yellow triangles down the top and widens slightly toward the tip into a modest club. The eyes do not meet on top of the head; a small ridge sits between them, which is the mark of the clubtail family. Freshly emerged animals show no green at all and take on the colour only as they mature. Males hold perches on sunlit stones, sandbanks and bare branches over shallow, fast water and patrol short beats low over the surface. They avoid shaded banks.

The larva is where the species' needs are set. It is a burrower, built with a flat, shovel-like lower lip and digging front legs, and it spends two to four years buried in the sand or fine gravel of a flowing river bed, taking whatever small invertebrates pass. It digs in almost the moment it touches bottom, at any current speed. That is why the species drops out of rivers that are straightened, dredged, lined with concrete or smothered in silt: whatever the water chemistry, there is nothing left to burrow into. The EU protects it under the Habitats Directive, and the loss of sandy river beds is the main threat named in its accounts.²

The Bolina is a regulated and polluted stream for most of its length. The ponds strung along it, Staw Bolina among them, formed out of mining, and the greatest variety of life on the stream is found at its headwaters and around those ponds, which is where both records sit. Whether a river dragonfly is breeding anywhere in that system is a question two sightings cannot answer. Adults of this species regularly wander several kilometres from the river they emerged in, into sunny clearings and along heated paths, before returning to water to breed.² August 27 sits inside the normal June-to-September flight season, a few weeks past the late-July to mid-August peak.²

So a dragonfly whose whole early life depends on clean, loose river sand was flying over a valley that mining shaped. Anyone walking the paths around the Bolina ponds on a sunny September afternoon can still look for a green-fronted dragonfly the length of a finger, sitting flat on bare ground or a stone, and know what it takes to make one.