23 JULY 1921, Page 16

HOUSE MARTINS.

[TO THE EDITOR OF THE " SPECTATOR."]

SIR,—Can your bird-loving readers inform me whether it is usual for house martins to keep a menage h troisl I have watched these little creatures building under my own and my neighbours' eaves, and in every case it took three to bring the mud and make the nest. Does this mean a cock with two wives or a hen with two husbands? Also, if it is common for sparrows to rob the martins of their nests as soon as they are completed, how is such shameless conduct to be prevented?—