Tree martins on a late summer evening dived and dunked into the stippled waters of the twin reservoirs at the Waterworks Reserve, sending up golden splashes that reflected the last rays of a dying sun.
The sunset provided a backdrop to the martin manoeuvres and, strangely, I recalled an exploding volcano in Iceland I had just seen on television, throwing droplets of molten lava into the air.
Tree martins were hitting the water in what is termed “splash bathing” and as they took the plunge it really did look like the reservoirs were on fire..
Tree martins are close relatives of welcome swallows and both aerial species are not adapted to life on the ground. They feed and take water on the wing, catching flying insects and taking a drink by dipping their bills as they skim the surface of lake or river. I’ve seen this drinking manoeuvre many times but was alarmed one evening to see the martins taking the ritual a little further – actually hitting the water in a giant splash. I feared for their safety, thinking they were taking risks, the risk of drowning on sodden wings, in order to drink on an exceptionally hot evening when the temperature had reached 31c.
No worry, the martins always emerged unscathed. One evening a flock of about 10 birds were at it, the scene reminiscent of the childhood game of skimming flat stones across the surface of a body of water, the martins bouncing along and leaving circles of ripples in their wake.
Because the behaviour was new to me, I consulted birding websites and bird books, immediately discovering it was common practice among the world’s swallows and martins despite its apparent dangers if the birds misjudged their plunges and ended up in the drink.
Returning to the Waterworks next evening, I confirmed the second part of the bathing ritual. The martins flew to a perch on a strand of electricity cables, shaking off the excess water and preening under the last rays of the sun.
Bathing is essential for all bird species because it keeps flight features in tip-top condition. The water removes not only dirt and dried and weathered feathers and skin, but parasites.
The martins certainly looked fresh and sparkling after their aerial bath. They are beautiful birds, dark blue on the back with silver undersides. They are smaller and appear far dumpier than the slender welcome swallows, whose streamlined appearance is enhanced by long tail feathers. So as not to compete for insects, the martins generally fly above the treetops, and the swallows at ground level.
When swallows and martins come together at the Waterworks Reserve, the martins can easily be separated by a patch of white feathers on their lower back, the rump.
On a summer’s night, both species can always be relied upon to bring a splash of colour.