To breed or not to breed: causes and imp
β
Markku Orell; Kari Koivula; Seppo RytkΓΆnen; Kimmo Lihti
π
Article
π
1994
π
Springer-Verlag
π
English
β 829 KB
Causes and consequences of non-breeding in willow tits were studied in northern Finland during 1986-1992. The breeding status was sex and age biased; males and yearling birds were in excess among the non-reproducers. Due to sex bias in the population it appeared detrimental for males to lose a mate,