Letters

--The habit, referred to by several contributors to this and the previous volume T f this journal (antea, Vol. xxxviii, pp. 206, 300, 360, Vol. > xxxix, pp. 159,160) in which parent birds of many species probe into the nest lining beneath the young, has been variously attributed to the eradication of parasitic insects; to a desire to shake up the lining, "air it," and prevent it becoming a caked mass...