------+---------+------+---------+------+------+---------+ Day | _Ammospiza caudacuta_ | Average | ------+---------+------+---------+------+------+---------+ 0 | 1.6 | ... | 1.8 | 1.7 | 1.7 | 1.7 | 1 | 1.8 | 2.3 | 2.5 | 3.0 | 2.1 | 2.3 | 2 | 3.3 | 2.7 | 4.1 | 4.6 | 3.1 | 3.6 | 3 | 5.0 | 3.7 | 5.9 | 6.4 | 4.7 | 5.1 | 4 | 6.8 | 5.4 | 8.4 | 9.1 | 6.7 | 7.3 | 5 | 8.6 | 6.9 | 10.7 | 11.2 | 9.5 | 9.4 | 6 | 10.2 | 8.9 | 12.8 | 13.0 | 10.9 | 11.2 | 7 | 12.1 | 11.4 | 14.5 | 13.6 | 12.3 | 12.8 | 8 | 13.5 | 12.9 | 15.3 | 14.5 | 13.3 | 13.9 | 9 | 12.2 | 13.4 | 15.9 | 14.9 | 13.6 | 14.0 | 10 | 12.7 | 14.0 | 15.5 | 15.0 | 14.0 | 14.2 | 11 | ... | ... | ... | 15.1 | 14.4 | ... | ------+---------+------+---------+------+------+---------+ [1] These weights are not figured in the averages; see text. Seven nestling Seaside Sparrows and five nestling Sharp-tailed Sparrows were weighed at 24-hour intervals until they left their nests. The birds were weighed in early morning before they had received much food. Weights of these individuals, and daily averages for each species are shown in Table 1. The weights in the zero column were of nestlings that had not been fed. The weight of one hatchling (1.9 gm.), which does not appear in the table, is included in the average for the zero column. Two young Seaside Sparrows, approximately a week old, fell out of a nest between 9:30 a.m. July 6 and 5:30 a.m. July 7. When I found them below the nest, at the latter time, their temperatures were far below normal, and they had lost a considerable amount of weight. These abnormally low weights were not figured in the averages. The weights of Sharp-tailed Sparrows 11 days old were obtained by confining the birds to the vicinity of the nest with a screen. [Illustration: FIG. 1. The development of the young of Seaside Sparrows (solid line) and Sharp-tailed Sparrows (dotted line) as evidenced by four linear measurements taken at 24 hour intervals.] At hatching and throughout nestling life and post nestling life Seaside Sparrows average heavier than Sharp-tailed Sparrows of comparable age (Table 1). Weights of adults of the two species that were netted or collected between May 6 and June 27, 1955, within two miles of Chadwick, Ocean County, New Jersey, follow: Fourteen males of _Ammospiza maritima_ averaged 24.2 gm. (21.9-27.4 gm.); three females averaged 22.3 gm. (19.8-24.4 gm.). Thirty-three males of _A. caudacuta_ averaged 20.7 gm. (18.0-23.1, 25.8 gm.); 14 females averaged 17.8 gm. (15.3-19.0 gm.), 2.9 gm. less than the males. One female Sharp-tailed Sparrow, weighing 23.1 gm., was not included in the averages because it had an egg with shell in the oviduct.