Nest.—Nests in small colonies, fastening the nests to the face of a rock. The nest is composed of blackish brown hair-moss and held together by the characteristic glutenous saliva. The eggs do not differ from others of this genus being two in number and pure white in color. The eggs of a set collected in Sibuyan, June 11, 1904, measure 18.2 by 10.9 and 17 by 11.6 mm.
This species has been very rare in collections; the only specimen in the British Museum in 1892 was a skin of doubtful locality collected by von Othberg. We have met with it on several islands; in Sibuyan and Calayan it was extremely abundant.
319. COLLOCALIA ISONOTA (Oberholser).
OBERHOLSER’S SWIFTLET.
- Collocalia linchi Sharpe, Hand-List (1900), 2, 90 (part); Oates and Reid, Cat. Birds’ Eggs (1903), 3, 77 (part).
- Salangana linchi McGregor and Worcester, Hand-List (1906), 59.
- Collocalia linchi isonota Oberholser, Proc. Acad. Nat. Sci. Philad. (1906), 58, 208.
Pi-ping-aú, Benguet.
Bongao (Everett); Luzon (Whitehead, McGregor); Mindanao (Koch & Schadenberg); Mindoro (McGregor, Porter).
Adult.—About the size of and very much like Collocalia marginata but without white margins to tail-coverts, and with more white on the abdomen.
Young.—The young bird resembles the adult in plumage but the tarsi are flesh-color.
Nest.—Composed of moss or lichens and placed on the ground in the protection of grass or ferns. Two eggs measure 22.3 by 13.9 and 21.5 by 13.9.