We saw this bird in our back porch in late August and wonder is it a finch species? Geraldine Woodgate, Kilkenny It is a juvenile goldfinch. Young goldfinches just out of the nest lack the blood-red face, white chin and black top of the head that male and female adult goldfinches have. Their heads are completely pale brown. They will acquire their striking head colouration after their first juvenile moult, which happens about three months after they hatch. Goldfinches (among other finch species) can have two or three broods a year, which is why hedge cutting is banned until the start of September. Niall O'Gorman (6) found and reported this sighting of invasive zebra mussels In May we spent a weekend at Lough Ramor in Virginia. My six-year-old pulled a rock out of the water’s edge and told me he’d found zebra mussels. We looked up pictures online and found a link to report sightings, which we did, as my son Niall insisted. We’ve since had an email back from the National Biodiversity Data Centre to confirm the sighting – it is the first report they’ve had of the invasive species there and their website will be updated in the coming weeks. It is so important for everyone to be made aware of the existence of this invasive species to try to limit further spread. Also, it’s great to have our young people vigilant and interested in our wildlife. Anna O’Gorman (on behalf of Niall O’Gorman, aged 6)Citizen scientists like Niall contribute a huge amount of valuable scientific data to the National Biodiversity Data Centre. This is not a butterfly spotted by Helene Scott, but a moth – a swallow-tailed moth, Ourapteryx sambucaria This is a photo of a butterfly which was attached to my window at Sandyford. On closer look I do not now think it is a butterfly. The window and surrounding area had been power-washed the day before and I think we disturbed its sleep. Could you please identify it ? Helene ScottIt is not a butterfly but a moth – a swallow-tailed moth, Ourapteryx sambucaria. It is a common enough moth that flies at night in hedges and large gardens. It is often attracted to lighted windows. It sleeps during the day, so your power-washing must have rudely awakened it. Mated females lay scarlet-red eggs under the leaves of ivy and many other woody trees and plants. The caterpillars feed on the leaves until the following June. They hibernate as caterpillars in bark crevices in the trees they feed on. The adult you photographed will lose its lovely lemon colour as it ages.Rosaleen Power saw this demoiselle damselfly in Courtown woods earlier this summer I saw this beautiful demoiselle damselfly in Courtown woods in late July. It was one among five others flying around and landing on leaves. They also landed on my sun hat and dress. Rosaleen Power This aptly named damselfly is typical of fast-flowing waters. The male, which you have photographed here, has a most beautiful metallic blue body and splendid dark wings with iridescent blue veins. The female is duller with dark brown wings and a green bronzy body. The males are territorial but will stray from their territory when seeking a mate. It is found commonly along the southern half of the country but there are no records north of a line from Clew Bay to mid Co Louth.This very small fly, called a Minettia inusta, recently visited Brigid Murtagh in Co Wicklow This lovely friendly little fly visited me, and I would like to know what it is please. Brigid Murtagh, WicklowThis very small fly is called Minettia inusta. Immature specimens feed on decaying vegetation while adults feed on the fungal spores on leaf surfaces. Adults fly during the warmer summer months. Overwintering typically occurs in the adult stage, with individuals hiding in sheltered terrestrial microhabitats until spring when the females lay eggs on moist decaying vegetation. Please submit your nature query or observation, ideally with a photo and location, using the form below or by email to weekend@irishtimes.com