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Foster and Kreitzman - Seasons of Life - Starlings



Type of Spiritual Experience


This shows it is not genetic, it is based on function and systems

A description of the experience

Seasons of Life – Russell G Foster and Leon Kreitzman

An 11 hour daylength in early spring triggers reproduction in British starlings.  The starling lays its eggs, but normally does not copulate again in the same year.  Only six weeks from the triggering of reproduction and while day-length is still increasing, the reproductive system of British starlings collapses.  Not far away, in the hills of Southern Germany starlings studied by Helga Gwinner at the Max Planck Institut fur Ornithologie, are regularly double brooded.  Such differences between the populations of the same species in the timing of the collapse of the reproductive system have been described for many birds, and these differences highlight the importance of local conditions in the evolution of seasonal breeding patterns.

The source of the experience

Foster and Kreitzmann

Concepts, symbols and science items


Science Items

Activities and commonsteps