circa.4300 BC to 2019 AD
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Wildlife Newsletter for the Township of Dalkey     
                    April / 2019 - Michael Ryan

Our first lizard sighting of the year. 25th February, 2019.                                         Image. M.Ryan

    Every year, around the end of April and the early days of May, a particular insect appears that hovers in the air in large numbers around woodland edges, hedges and rough grass. We always see them on the ‘Green Road’, the path above Vico Road which is a real sun trap. Last year there seemed to be a higher proliferation than usual and any time we were there they seemed to cause a degree of consternation with passing walkers since they hover at head height and don’t make any attempt to avoid approaching people. A neighbour asked me were they flying ants. I heard somebody else wondering were they mosquitoes as they swatted them out of the way while somebody else sitting on a bench pronounced, with great authority, that they were horseflies, which have a very unpleasant bite.
     But they weren’t horseflies, nor were they ants or mosquitoes. They are in fact a type of fly, Bibio Marci, more commonly known as St. Mark’s Fly since they first appear with great regularity around the date of that saint’s feast day, April 25th. Sizeable creatures, shiny black and hairy with a long abdomen, they hang in the air almost motionless with long legs dangling underneath them. Their ‘in your face’ mannerisms adds to their lack of appeal making them seem even slightly sinister and threatening but in fact they’re totally harmless to humans and can be very beneficial to the environment.     The ones hanging in the air are the males of the species which only live for a week. They hover or sluggishly move up and down to attract females and according to ‘the male’s eyes are divided by a groove and have separate connections to the brain. This allows the males to use the upper eye part to look out for females and the lower part to monitor their position in relation to the ground, allowing them to hover in the same position. After mating the females lay eggs in the ground. When the larvae hatch they develop in soil where they feed on roots.
     They can cause damage to vegetables and plants in a garden but they themselves can be a important food source for birds to feed to their chicks. Buglife, anorganisation dedicated to insects with the charming motto ‘Saving the small things that run the planet’ goes on to say the adults are ‘very useful creatures, they feed on nectar, making them important pollinators of fruit trees and crops’ so if you encounter one be merciful, it won’t harm you despite its threatening stance.
    We were very surprised when Lucy spotted a lizard beside the path on Dalkey Hill in the last week of February. Normally Common Lizards, our only native reptile, wouldn’t be coming out of hibernation until March but, of course, normal barely exists any more as regards to the climate and seasons. A lizard needs to increase its body temperature to near 30 degrees Celsius (86 degrees Fahrenheit) before it can hunt effectively and the mini heatwave at the end of February created record high temperatures. This lizard was motionless, warming in the sunshine, its greenish brown colouring making it virtually invisible and it was only when a spider got too close we saw it suddenly transformed into a blur of motion as it dived on the spider and swallowed it. The following day Lucy spotted one again and we knew it was a different individual. The one we’d seen the previous day had a shorter dark tail with concentric circles indicating it had utilised its only defence against predators, the ability to shed its tail when attacked, leaving the confused predator, possibly a cat or kestrel holding a still twitching severed tail.
     The tail will grow back but much darker and stubbier. It’s not the only part of their body they can lose and another day my sharp-eyed companion found a coil of shedded skin a lizard had discarded, the lizard presumably wanting to begin its year with a fresh new wardrobe! At no small expense, we upgraded our bird feeders getting new peanut, fatball and sunflower feeders which all claim to be squirrel-proof and so far, thankfully, they have proven true to their word. Grey squirrels were taking loads of seeds as well as keeping the birds away and attempts to make the feeders squirrel-proof under upside down hanging flower pots on elongated wire hangers, only proved a minor temporary irritation to the greys. A previous ‘squirrel-proof’ feeder I had bought should more accurately have been described as a squirrel back support since the squirrel would easily squeeze through the vertical bars and stand with its back pressed against them as it nibbled away but the new ones we got are of much better construction with horizontal as well as vertical bars. Most are feeders inside a wire cage through which no squirrel could fit but one is a very clever device which is weight sensitive so if anything heavier than a bird lands on it the seed holding part retracts closing the feeding apertures. You’d nearly feel sorry for the squirrels trying in vain to get at the seeds so near and yet so far and not even being able to shake them out on to the ground. Able to put out peanuts again in the new feeder, within days we were delighted to have Long Tailed Tits and Siskin feeding from it.

St. Mark’s Fly, not the most handsome of beasts but a
very useful pollinator. Image: M. Ryan