A Nesting Study of the Pine Siskin (Spinus Pinus) at Hays, Kansas

Nesting of the Pine Siskin (Spinus pinus) was studied at Hays, Kansas during the springs of 1978 and 1979. Although Hays represents an isolated outpost beyond the major range of the Pine Siskin, no important differences in breeding biology were noted. Breeding populations were similar both seasons despite extreme differences in winter populations. Aspects of breeding biology studied included type and duration of nest building and nest placement (in pine, juniper and spruce trees). Mean clutch size (3 .1), mean incubation period (14.3 days) and mean fledging period (12.8 days) were determined. Hatching success and fledging success were determined and compared for nests in each of the three conifer types used as nest sites. Measurements (weight, beak length, tarsus length, tail length, length of fourth primary) of young were recorded daily to establish regression coefficient values of growth rate for the Hays nesting population. The influence of temperature upon the date of nesting was studied and compared with findings of an earlier study in Nebraska.