The key physiological cue for migration would be the changes during the day size. These modifications are associated with hormonal alterations during the birds. Within the interval ahead of migration, quite a few birds display better activity or Zugunruhe (German: migratory restlessness), initial described by Johann Friedrich Naumann in 1795, https://aquarium-care-uae55432.blogmazing.com/36666969/rumored-buzz-on-parrot-care-basics-dubai