THE BREEDING BIOLOGY AND BEHAVIOUR OF THE CONTINENTAL GOLDFINCH CARDUELIS CARDUELIS CARDUELIS.

Abstract

Summary. The breeding biology of the Continental Goldfinch was studied intensively during 1943 at Eichstatt, in Bavaria. The habitat, status and relations to other animal species are described. The call‐notes and their interpretation are discussed. The Eichstatt Goldfinches established their territories at the same time as they selected their nest‐sites. The territories functioned as mating and nesting stations, and were only occupied when the nest was in use. Throughout the breeding season paired birds continued to flock in small numbers. Display postures have been separated into three categories: territorial, aggressive, and sexual “contact” displays. Where one posture is used in different situations, confusion is avoided by differences in the time factor and the external and internal situations. Heights and positions of nests are summarized. Nest‐site selection and building are described. The first egg was usually laid within one or two days of the end of intensive nest‐building. Partial incubation began with the first egg, and complete incubation probably began with the last but one. Three females incubated their egg for 12 day±½ day, 11¾ days ±½day, 11½ days ½ day respectively. The same females incubated their eggs 96%, 93%, and 87% of the observed time. The female was usually fed on the nest by the male. During periods on the nest the females were active in attention to the nest, eggs, self, and the sex partner when present. Nestlings of three pairs hatched in 26½, 21, and 9 hours. The females ate the shells. The young remained in the nest 16 days 2 hours ± 15 hours, 15 days 20 hours ± 20 hours respectively. The third nest was blown out of the tree. While on the nest the females were very active. Some of this activity shows a lack of “concentration”. While feeding the nestlings the male fed the female and she then regurgitated the food, sometimes in a large number of small beakfuls. Later the nestlings were fed direct by either adult. The hourly average rate of defecation rose during the first three days, and after the seventh day decreased. The behaviour of the nestlings is described. After leaving the nest their powers of flight increased rapidly.