(Reading time: 2 mins.)
On my way to Griffiths Park in the Glasnevin-Drumcondra area on Monday I stopped to gape at a glitter-storm above the street. They were flies, dancing in the sunlight, the slanting light reflected off them. In the Park itself through which the Tolka flows, I saw many more clouds of them, always in patches of the early evening sunlight. These were the Mayfly or Cuil Bhealtaine. I took photos but my phone was unable to capture their true beauty, coming out in the photos more like snowflakes.
At one point I was able to observe a cloud of them at closer distance. They didn’t all just fly around haphazardly – every now and again individuals would dive down like a meteor – the sun making them seem as though they had a burning trail — and then zoom up again. On and on they went and it amazed me that no birds or bats seemed to be preying on them.
A poem or a piece of music might have done the sight justice.
The mayflies rise from their larval stages underwater only to procreate, to open their wings and fly, then to mate and to lay eggs into the water. They cannot eat as they no longer have mouthparts and individuals that are not seized and eaten by other life-forms have at most a couple of days to live.
A great many life-forms, especially invertebrates, spend their youth in the water and rise to mate. Dragonflies and damsel flies do so – a return to ancient mother water for some, perhaps. Long ago the cetaceans – whales and dolphins – ‘returned’ to sea and evolved to adopt to it, limbs converted to fins and tail. Penguins did the same, wings becoming flippers. And mayflies are quite an ancient life form too.
As a child and into my early teens I would spend hours by a pond or other stretches of water, looking at what I could see of the animal life there, also sweeping a long-handled net through the water and bringing my assorted catch home to examine in jars or basins of water.
The larvae or nymph stages of water-laying flies comprised a large part of the collection: midges, gnats, mosquitos, rat-tailed maggots, stoneflies, bloodworms and also the larvae of the dysticus beetle (handle with care!). These and more shared the murky waters with daphnia and rotifers, leeches and planarian worms, water-mites, frog and newt tadpoles while water-scorpions, water-measurers, pond-skaters and water-margin spiders prowled the surface above like pirates.
In clearer water such as streams and rivers, I caught sticklebacks while caddis fly larvae inside their home-made tubes imitated drowned twigs.
But I don’t recall ever seeing mayflies and certainly never saw a hatch like this. No doubt trout anglers have seen the like often for such mass ‘hatchings’ are a bonanza for them. From boat or land they cast out their lines with articifial flies attached, hoping the trout rising to snatch at the mayfly harvest will grab the false fly instead. These hooks with bits of feather or fibre tied around them don’t look like a fly to you or me but sitting on top of the water and seen from below, they must look good enough to eat.
ON THE WAY BACK
There was more to see, like the mallard duck with her clutch of chicks or ducklings but the intervening branches made a photograph impossible. In shape and colour the new ducklings remind one of bumblebees and they zip around on the water without difficulty and fearless. Alas, they have a high attrition rate as seagulls and herons will each take them as a snack.
Looping around on my walk I passed by the closed Botanic Gardens looking great in the sunset but I had to stalk the view from the side to get a shot clear of the scaffolding inside and signpost outside in front.
On the bank of the Royal Canal on the home stretch a heron was standing close to the path but I delayed too long getting my camera ready so it became uneasy and began to move off. Further along, a swan couple kept their cygnets close, just a couple of days old at most, balls of grey fluff – Anderson’s “ugly ducklings”.
But the day’s prize for me was undoubtedly the clouds of mayflies in their glittering dance in the sun.
SOURCES/ FURTHER READING
In general: https://en.wikipedia.org/wiki/Mayfly