For me, a sad time of the year is when the swallows congregate on the wires for their annual migration. This week I saw two be- side each other - one with the usual dark wings, the other pure white. I've heard of albino blackbirds, but never swallows.
Vivian Gardiner, Lauragh, Co Kerry.
Albinism is rare but widely spread among birds, and at least one other white swallow has been observed in the life of this column. Anything that singles out a bird so boldly among its fellows is likely to bring a higher risk of predation, so the gene for albinism is unlikely to persist for long in one swallow family.
At Fermoyle beach, on the north side of the Dingle Peninsula, in July, I saw many hundreds of hermit crabs at the water's edge. I had previously seen them only in small numbers in rock pools. Is there an explanation for this gathering?
Michael Carr, Rochestown, Cork.
There are records of years of great abundance among the tiny hermit-crab Diogenes pugilator in which large numbers are washed ashore at the edge of the incoming tide; they quickly bury into the sand. This may have been a similar phenomenon.
Edited by Michael Viney, who welcomes observations sent to him at Thallabawn, Carrowniskey PO, Westport, Co Mayo. E-mail: viney@anu.ie. Observations sent by e-mail should be accompanied by postal address.
