Eye on Nature

While walking around Lough Leanna, near Castlebar, I heard a commotion and saw a heron flying awkwardly about nine feet above the water and being dive-bombed viciously by two screeching seagulls. They eventually made contact and it fell in the water. Can a heron swim, and had it robbed the gull's nest?
Paddy Touhy
Castleconnell, Co Limerick

A heron can swim and it had at least got too close to the seagulls' nest.

Could you advise me about the brown, slimy-looking alga growing on the gravel in our garden. Is it harmful to animals?
Gina Hetherington
PAWS, Mullinahone, Co Tipperary

The alga growing on your gravel is Nostoc, a blue-green alga which appears in waterlogged ground. It is not harmful to animals. Better drainage would help.

Jackdaws are nesting in our chimney and on the day I presumed their eggs hatched another pair of jackdaws arrived. A furious battle ensued in the air and on the ground.
Caomhá n Mac Murchaidh
Béal an Átha Mó ir, Liatroim

A pair of jackdaws for some reason were looking for a late nesting site and perhaps they had fledged from that chimney.

Michael Viney welcomes observations at Thallabawn, Carrowniskey PO, Westport, Co Mayo, or by email at viney@anu.ie. Please include a postal address