Who’s this crabby customer? Readers’ nature queries

Ethna Viney on the common shore crab, mutant daisies and skeletal remains

Common shore crab
Common shore crab

I found this crab on the beach at Brittas Bay. The strong blue colour was so attractive; is it a native? – Anne Doyle, Wicklow town
It's a native: the common shore crab, which is variable in colour.

Birch crown gall
Birch crown gall

I recently came across these growths on a birch tree. My walking companion thought they were wasp galls, which she said were more usually found on oak trees. What are they? – Brona Duddy, Churchill, Co Donegal
The growth in your photo is birch crown gall caused by a bacterium.

Skate or ray bone
Skate or ray bone

This was found on Bunduff strand, Sligo. It's cartilage, not bone. Is it from a skate or a ray? – Heather Wood, Cliffoney, Co Sligo
It could be from either – the skeletons are similar.

Shag
Shag

While walking the back of the West Pier in Dún Laoghaire, we came across this bird with a crest and dark green eyes. He apparently had just won a stand-off with a large dog. Is it a cormorant? – Nicky Boyle, Blackrock, Co Dublin
Your bird is not a cormorant but a shag in early summer plumage. The shag is smaller than a cormorant.

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Fasciation
Fasciation

I found this funny daisy in my garden. It looks like a mutant daisy, with lots of daisies all growing together. – Nora Bealin (10), Ventry, Co Kerry
This is a phenomenon called fasciation. It can be caused by genetic mutation, bacterial or viral infection, or damage to the growing point of the plant. It can happen in other plants, but I've seen it most often in daisies.

Turtle
Turtle

My daughter, Niamh Lynch, found this turtle on Rush Beach while out walking yesterday. – Brendan P Lynch, Ennistymon, Co Clare

Ethna Viney welcomes observations and photographs at Thallabawn, Louisburgh, Co Mayo, F28 F978, or by email at viney@anu.ie. Include a postal address