Eye On Nature

I heard recently on the radio, in reference to the Sweeney cull of basking sharks off Achill Island in the 1940s and 1950s, that "they never came back". I remember well the endless publicity this company got for recovering the shark oil. Did they really extinguish the species in the area?

Joseph Clarke, Greenfield Park, Dublin 4

Basking sharks are still seen in the west-Mayo area but not in the same numbers as 50 years ago. They move from area to area following drifts of the plankton on which they feed. In late spring and summer, there are often large numbers of basking sharks in the Isle of Man region of the Irish Sea.

At the end of November, two birds appeared in an old nest on our porch and stayed there. They appear brown with a speckled breast, almost like a thrush and are bigger than those that nest there. Is it usual for birds to do this in winter - are they taking shelter for the colder months?

Antoinette Daly, Kildare

Wrens are noted for roosting together for heat in cavities or old nests during the winter.

Edited by Michael Viney, who welcomes observations sent to him at Thallabawn, Carrowniskey PO, Westport, Co Mayo. E-mail: viney@anu.ie (E-mails should include a postal address.)