Salivary Glands in the Black Swift
Salivary Glands in the Black Swift.-In 1956 Lack (Auk, 73, 1956: 2) stated that all swifts use saliva in their nest building and that “all, so far as known, have enlarged salivary glands in both sexes in the breeding season.” These general statements were questioned, however, by Johnston (Condor, 60, 1958:79) especially with regard to the Black Swift (Cypseloides tiger). This species has been reported by Bent (U.S. Nat. Mus. Bull. 176, 1940:256-260) and Legg (Condor, 58, 1956: 183) to nest in situations where saliva would be unnecessary for construction of the nest; in fact, both men stated that saliva was not used in the nest. These reports do not preclude the possibility that Black Swifts do have salivary glands but just do not use them in nest building as do sdme other swifts.
An opportunity to resolve these apparently conflicting statements presented itself when I came into possession of two specimens of Black Swifts preserved in alcohol. The adult birds, a male and female, were taken at random from a flock at Vancouver, British Columbia, on June 13, 1960, by Dr. Miklos D. F. Udvardy. At this time the birds should have been nesting; the male had testes 9 mm. in length and the female had follicles 1.5 mm. in diameter. Gross examination of the floor of each bird’s mouth did not reveal the presence of salivary glands which are so conspicuous in C/zaeturu and Couocalia (Johnston, Condor, 60, 1958:80; Marshall and Folley, Proc. 2001. Sot. Lond., 126, 1956:385), SO histological sections of the floor of the mouth were prepared. After staining with hemotoxylin and eosin, these sections showed a few small lobes of the sublingual salivary glands, but each of these lobes was only 400 c or less in diameter whereas those of the Chimney Swift (Chaetwa pelagica) were shown by me earlier to be as much as 1000 U.
From these data it is evident that the Black Swift does have sublingual salivary glands but that these glands are smaller than those found in some other swifts. These observations support the contention by Bent and Legg that saliva is not used in nest construction of this species.-Davm W. JOHNSTON, Department of Biology, Wake Forest. College, Winston-Salem, North Carolina, January 5, 1961.
