What is this strange growth outside Cork University Hospital?

Éanna Ní Lamhna on fungi, a marine worm and whooper swans

Sulphur tuft fungus. Photograph supplied by Greg O'Connor
Sulphur tuft fungus. Photograph supplied by Greg O'Connor

These grape-sized, mustard-coloured fungi have sprouted up outside Cork University Hospital, in a place where poplar trees once grew. Any idea what they are? Greg O’Connor, Cork

This is a beautiful photograph. Mycologist Hubert Fuller says that it is a young developing stage of the sulphur tuft fungus, Hypholoma fasciculare. It always occurs as yellow to yellow-brown clusters that grow on both deciduous and coniferous wood and, as in the image, on wood chippings. If visible, the gills would have a greenish-yellow hue, but it can occur in such tight groups that the caps do not have room to expand. It is widespread and very common, occurring through summer to midwinter.

Sawfly caterpillar. Photograph supplied by Jason Cross
Sawfly caterpillar. Photograph supplied by Jason Cross

What is this caterpillar-like creature, which I recently found crawling up the side of the back door? Jason Cross, Co Cork

It does look like a caterpillar, right enough, but it will grow up to become a sawfly rather than a moth or butterfly. Sawfly larvae have at least six pairs of stumpy fleshy prolegs behind their three pairs of real legs, whereas moth and butterfly larvae never have more than five. We have to imagine the six pairs of back legs here, as the photo only shows the top side of the insect.

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Lichen. Photograph supplied by Monica Hall
Lichen. Photograph supplied by Monica Hall

I spotted this lovely item while collecting fallen twigs from under the sycamore on the grass verge. The photo shows the back, which seems to have a little root/sucker. Is it a type of lichen, fungus or other organism? Was it growing on a branch of the tree? It is about two inches in diameter. Monica Hall

This is a lichen – Ramalina fastigiata, which was growing on a branch or a twig of the tree. It just has a small sucker or holdfast rather than roots, and it gets all its nutrients from the rain and the air. It is extremely sensitive to air pollution, so to get such a fine tuft of it indicates clean air quality wherever the tree was.

What is this bird that our cat chased into the house?Opens in new window ]

Marine worm. Photograph supplied by Cee Warfield
Marine worm. Photograph supplied by Cee Warfield

Please identify this creature, which was washed up on Ballymoney Beach in Co Wexford. Cee Warfield

This is a marine worm, which goes under the misleading name of sea mouse. When alive and in the whole of its health, its body is covered with a fur of brownish-grey hairs that may be matted with mud. It also has a band of longer brown and greenish bristles along the sides. It lives below the high tide mark underwater but sometimes it gets washed up alive and it can plough its way through the muddy lower shore. This one is long dead, however.

Whooper swans and white-fronted geese. Photograph supplied by John Glynn
Whooper swans and white-fronted geese. Photograph supplied by John Glynn

I saw a small flock of whooper swans and some white-fronted geese on Farrihy lake in west Clare on November 21st. John Glynn, Kilrush

Both of these species are winter visitors to Ireland. The whooper swans we see here breed in Iceland and arrive from their breeding grounds in family groups. It is called a wild swan because, unlike the much tamer mute swan, it avoids human contact. It makes high-pitched trumpeting sounds and is the swan referred to in Irish legends such the Children of Lir. The most recent census (2020) counted 19,111 here – the most ever. The white-fronted geese that come here in winter breed in Greenland. Ireland is internationally important for these birds as a third of the world’s population overwinter here – four-fifths of them on the Wexford slobs. Worldwide numbers of these geese have dropped alarmingly in recent years from 21,500 in 2019 to just 15,000 in spring 2024. Breeding success seems to have been very low in Greenland during the last two breeding seasons, at about 2-3 per cent.

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Éanna Ní Lamhna

Éanna Ní Lamhna

Éanna Ní Lamhna, a biologist, environmentalist, broadcaster, author and Irish Times contributor, answers readers' queries in Eye on Nature each week