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Wildlife Newsletter for the Township of Dalkey
                          April / 2017 - Michael Ryan

A Treecreeper: Its curved bill, open here, is the thinnest beak of any of our bird species and used to pry out
insects or their eggs from little fissures in the bark of trees.                                                   Photo: M. Ryan

  High flyer – Just past the Aircraft Beacon on top of Dalkey Hill a little bird moving through the gorse bushes looked different enough to warrant a closer inspection and through the binoculars I was able to see it was a male Stonechat. Not uncommon along the gorse beside the railway line and often seen near the Ramparts below the Vico I can’t recall seeing one so high up before, although they used occasionally be seen and probably nested on the lower, middle level of the quarry. Handsome, Robin sized birds, with a reddish breast, white collar and the male developing a smart dark head in the breeding season, the stonechat’s name derives from their call, likened to the sound of two stones being knocked together. This little area on the top of the hill with a few scattered trees and lot of gorse resembles raised heathland or mountain side habitats and in the past has attracted linnets and whitethroats and some years ago even having a meadow pipit displaying, flying upwards singing and then gliding down, wings outstretched in what is known as a parachuting display. The fact it is potential meadow pipit habitat might also be the reason why, when paying their infrequent visits, cuckoos have often called around this particular area, meadow pipits being their favoured host species in whose nest they lay their own eggs.
After Doris Day – On our first walk over the hills after Storm Doris we could see it had
inflicted some serious damage around the woodlands with the trunks of a number of mature
trees split in half and some very large branches brought down. We were concerned about the fate of the red squirrels, hoping their drays hadn’t been dashed to the ground while they
sheltered in them. One of the most reliable parts of the woods for seeing them in proved
empty but then, as we emerged from that Scots Pine grove, tearing around a oak tree in front of us was a pair of reds. Whether they’d gone into the securely positioned nest boxes or
moved to the more sheltered side of the hill they’d survived the ferocious winds and later further up the hill we saw two more reds. After wind gusts of up to 120km a hour had lashed the country bringing down power lines and tearing tiles off roofs, up in the trees, still in place, were squirrel drays and birds nests which, although constructed only with a pair of claws and a mouth or beak, had survived the worst nature could throw at them.

Running like clockwork – Recently, when opening a webpage on the BBC radio site, a recommendation for a programme brought me to a very interesting wildlife programme, The Countryside Hour, a weekly feature from Radio Norfolk. Questions and observations about birds would be sent to this radio programme where a specialist guest would answer listeners’ queries. One man had phoned in to say he often had Treecreepers visiting a tree in his garden. Treecreepers always move upwards on tree trunks, never down, in a spiralling movement using their stiff forked tail to brace them against the trunk as they extract insects grubs and eggs with a slim curved bill. This listener had noticed any time he’d seen them they always circled the tree trunk in a clockwise direction, never anti clockwise, and he wondered was that always the case. This query totally bemused the ornithologist expert who admitted he had no idea as he’d never noticed but thought it a fascinating observation and was evidently going to pay a lot more attention next time he saw a Treecreeper. Next time I saw one on a tree trunk I watched but couldn’t figure what way it was going up the tree. When it wasn’t on the farther side of the trunk out of sight it was at the front going vertically up the bark. Some years ago a few members of the South Dublin Branch of birdwatch positioned some nest boxes for Treecreepers on a few trees on Killiney Hill. The Treecreeper boxes have a downward slanting front and a small opening on the side. When putting up nest boxes in parks it’s always important to have them out of the reach of curious people. Any of the boxes we put up could only be accessed by ladder so I was never able to check them out to see if there was any signs of occupancy. I don’t know if any of our boxes were ever used, traditionally there’s a low take up of Treecreeper boxes, especially if there’s any good natural sites and since putting up the boxes we’ve found a number of natural Treecreeper nests in the vicinity, one in a dead trunk and others behind the bark of older trees.

           Jay bringing food to its nest.                          Photo: M. Ryan

The Jay Way – Birds will rub their beaks against branches to clean off remains of food but the jay I was looking at wasn’t just cleaning its bill. It was too far away to see precisely what it was holding in its bill but it was either a fat insect grub or a caterpillar. As I watched, it meticulously wiped it backwards and forwards against the branch it was perched on as if it was cleaning it, sometimes laying it gently on the branch before delicately picking it up again, possibly turning it over before repeating the process. Some species of caterpillars have defences to make them unpalatable to predators and are often brightly coloured to signal they‘d be a bad choice for a meal. These caterpillars can be covered in urticating hairs, the word ‘Urtica’ is Latin for ‘nettle’ and these hollow hairs when broken emit the same painfully irritating fluid you’d get from a nettle sting. This should deter many predators and if they do ignore the discomfort and swallow the caterpillars the hairs are indigestible and have to be spat out. What many species of birds do and possibly what the jay I saw was doing, was brushing (or ‘scrubbing’ as it is known) a caterpillar against the bark to try and remove as many hairs as possible and make it more palatable before swallowing it. As they say with cooking, it’s all in the preparation.