The primary physiological cue for migration would be the variations from the day length. These variations are connected with hormonal changes inside the birds. During the interval before migration, a lot of birds Exhibit bigger exercise or Zugunruhe (German: migratory restlessness), initially described by Johann Friedrich Naumann in 1795, and https://buy-cat-products-online59146.topbloghub.com/44101481/not-known-factual-statements-about-bird-ownership-checklist-uae