is, therefore, entitled to the credit of discovery. Sixty-one years had
passed since Macgillivray's visit, during which no knowledge of the
life-history of the bird which spends most of its time hawking for
insects in sunshine and shower had been revealed, when a fragment of a
nest adhering to the roof of a cave on one of the highest points of the
Island attracted attention. Submitted to an expert (Mr. A. J. Campbell,
of Melbourne, Victoria), the identity of the builder was guessed.
Subsequently I had the satisfaction of finding a colony close to the
water's edge, on the weather side, where the birds had frequently been
seen darting among blocks of granite almost obscured by jungle.

No nests were found in crevices deemed to be favourable spots, though
the predilection of the genus for gloom was appreciated, but upon the
exploration of a confined cave the excited flutterings of invisible birds
betrayed a hitherto well-kept secret. When my eyes became accustomed to
the dimness I saw that the roof of the cave (which is fairly smooth and
regular with an inclination of about thirty degrees) was studded with
nests. Fifty-three were placed irregularly about the middle of the roof,
some in pairs, none on the walls. Some were not quite finished; twenty
contained a single white egg each; none contained young. All were
adherent to the stone by a semi-transparent white substance resembling
isinglass, with which also the fine grass, moss, and fibre composing the
nests were consolidated. The vegetable material of the first fragmentary
nest (found September 17, 1908) was quite green and the gluten moist and
sticky. Those now described (two months later) were dry and tough, the
dimensions being 2 to 21 inches across and about 3 inch deep. The cave is
only about 30 feet above high-water mark and the entrance the birds
favour is, strange to say, averse from the sea and much obscured by
leafage.