|Publication Type:||Journal Article|
|Year of Publication:||1977|
|Keywords:||Fringilla, Fringilla coelebs, Fringillidae, Norway|
Seasonal song diagrams are given for more than 20 species in forest areas in South Norway, based on 700 surveys 1968-74. Song activity was closely related to breeding cycle; double peaks were common. Maxima were reached a few days prior to egg-laying. Song activity could therefore also be used to analyse proximate timing factors for breeding. Correlations were found with temperature, snow-melt and phenophases of birch and two invertebrates, being very high in 'early' bird species. Multiple regression analysis indicated that the song peak for Fringilla coelebs was advanced when the spruce cone crop was rich; termination of song activity in summer was positively correlated with start of laying in spring and tended to occur later in warm and wet weather. The hypothesis that the breeding times of birds show smaller displacements than do the environmental phenophases is supported.
|Short Title:||Ornis Scandinavica|