Michael Viney responds to reader's queries and observations on nature.
A lone pied wagtail visits the bird feeders outside our kitchen window. He (or she) flies on to a suspended half-coconut and after two or three turns he flies directly into the glass window pane about two feet away. He does this repeatedly without learning that he can't go through.
Frank and Erica Storrs, Dunfanaghy, Co Donegal
The wagtail sees his reflection in the glass as an interloper into his territory, so he attacks it. If you put a cutout of a hawk in the window, he will stop.
On a recent walk beside the Grand Canal near Robertstown I came across some clam-like shells on the bank.
Dermot Mac Dermott, Robertstown, Co Kildare.
They were probably freshwater duck or swan mussels, which are plentiful in the canal.
A friend told me that when he was a boy, game wardens paid four shillings for grey crow fledglings and two-and sixpence for magpies. I have never heard of anyone doing this now, so maybe that is the reason for the increase in population.
Mary Legge, Ballinamore, Co Leitrim.
The increase in the population of magpies, or grey crows, is due mainly to the greater availability of food - rubbish bins in towns and the feeding of livestock in the country. Gun clubs that rear pheasants regularly put a bounty locally on foxes and grey crows but this rarely impacts much on numbers.
Edited by Michael Viney, who welcomes observations sent to him at Thallabawn, Carrowniskey PO, Westport, Co Mayo. E-mail: viney@anu.ie (include postal address)