194 U.S. NATIONAL MUSEUM BULLETIN 237 part i 



some birds content themselves with four. Despite the difference in 

 latitude (10°) large clutches occur as regularly toward the southern 

 limit of the breeding range, in southern Norway, as in the extreme 

 north. Even in a small series these eggs show considerable variation. 

 In color they range from a clear blue to a dull olive, with markings of 

 dark brownish pm-ple, reddish brown, and lilac, some being heavily 

 blotched, others thinly spotted, while in quite a number the overlying 

 pigments are smeared to give an attractive clouded effect. Henry 

 Seebohm (1884), one of the authorities of his day, recorded immac- 

 ulate specimens. The type most frequently seen has a greenish 

 ground with brownish-purple streaks and blotches, which often show 

 a penumbra of paler shade. Another less common but very charac- 

 teristic type of the species is a clear, pale blue relieved by scattered, 

 almost black spots. In a third variety, on the other hand, the grayish- 

 blue ground color is almost completely overlaid with flecks of reddish 

 pigment, some such eggs being very handsome. The least attractive 

 specimens are grayish buff with few and very small markings. One 

 hundred eggs measured by Jourdain averaged 19.5 by 14.6 mm., 

 maximum 22.2 by 15.6 mm., minimum 18.1 by 13.5 mm. 



Eggs of the brambling may easily be confused with those of the 

 chaffinch. If normal types are compared, those of the former species 

 will appear the darker and greener, but this cannot be regarded as an 

 entirely reliable diagnostic character. As the chaffinch breeds 

 alongside its ally over a wide area, the greatest care must always be 

 exercised in identifying nests. 



Young. — Very little has been recorded of the incubation and 

 fledging periods of the brambling. M. A. England, who kept two 

 nests under close observation, found that the female alone covered 

 the eggs throughout an incubation period of 14 days. After the eggs 

 had hatched, the bird was seen to remove the shells, which she carried 

 some distance away. The male, as far as could be discovered, took 

 no interest in the nest until the young appeared, when he came to 

 feed his mate and, later, the brood. England's notes suggest that the 

 female did not settle down to incubate before the last egg was laid. 

 On the other hand, the owner of a nest found by Congreve certainly 

 started to incubate before completing her clutch, some of her sLx 

 eggs containing noticeably larger embryos than others. Svein 

 Haftorn (1952) records a family of six young examined on July 23, 

 1952, of which one was at least 4 days old, while another had just left 

 the shell. In June 1938 Blair found a brambling sitting hard on three 

 eggs in southwest Norway. None of the eggs showed any trace of 

 incubation, however, and the sitting bird may have been only covering 

 them against the heavy rain which was falling at the time. 



