phenology

from The Collaborative International Dictionary of English v.0.48

Phenology \Phe*nol"o*gy\, n. [Contracted from {Phenomenology}.]
   (Biol.)
   The science of the relations between climate and periodic
   biological phenomena, as the migrations and breeding of
   birds, the flowering and fruiting of plants, etc. --
   {Phe`no*log"ic*al}, a. -- {Phe`no*log"ic*al*ly}, adv. --
   {Phe*nol"o*gist}, n.
   [Webster 1913 Suppl.] Phenolphthalein