EEB386H1 Lecture Notes - Lecture 6: Early Summer, Phenology, Night Hours
14 Apr 2017
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Document Summary
Rwbb could come early will get good territory but risk freezing. If come late might not have any territory left: usually young males. But later = better survival because warmer, more food. Have to pack in number of life-history stages and not a lot of wiggle room. In rwbb have population variation in arrival time: global arrival time could move. Looking at how birds fit parts into lifecycle. Spring equinox: when day and night hours are the same. Summer solstice: 15 hours of day, 9 hours of night. March 21st: start of spring season, growing season, various definitions of spring, spring is actually defined in biological terms as start of growing season. Ex: when leaves unfurl on certain indicator trees. Most birds have an annual lifecycle: breeding, moult, migration. Each of these stages are mutually exclusive: can overlap a bit (i. e. tradeoffs - migration and breeding season in rwbb, but mostly birds can"t do 2 things at once.
