Michael Viney responds to queries and observations on nature.
Recently I picked mussels with a friend who said there might be small crabs inside the shells and that they eat their host. We found three cooked crabs.
Doutsje Nauta, Achill, Co Mayo
They were tiny pea crabs which lodge with their host first of all in trough shells until they form a hard shell. They leave the shell, mate and find a second host in mussel shells. The pea crab feeds on the food collected by the mussel but does not harm its host.
On frequent visits to the Killary and Doolough regions, we see sheep grazing along the shoreline. Are they eating seaweed?
Victor Douglas, Newtownabbey, Co Antrim
Yes. On North Ronaldsay, in the Orkneys, sheep feed on seaweed and are prized for the special flavour of their meat.
Magpies are taking the food I put out for the smaller birds and they have now adapted to feeding from the nut feeder.
Colin Rogan, Rathgar, Dublin 6
Put net wire around your bird table and feeder and you will discourage the magpies.
• Send observations to Michael Viney, Thallabawn, Carrowniskey PO, Westport, Co Mayo; e-mail: viney@anu.ie (include a postal address).