They don't, they are there all the time it is just that you hear them more easily early in the morning after they wake up and there is less outside noise covering their sounds.
it is just a reaction
chirrup, chirp, twitter, tweet, sing, whistle
Like all other birds hummingbirds communicate by chirping and singing. They have a short high pitched chirp. This chirp is easily recognized from other birds songs or chirps.
they run away
Yes, the word 'chirp' is both a noun (chirp, chirps) and a verb (chirp, chirps, chirping, chirped).Examples:You can hear the chirp of the baby birds. (noun)They will chirp until their mother returns with food. (verb)
The reason that birds chirp in the morning is that the resonance of the rising sun bounces of the earth creating a sound with a frequency to low to be heard by the human ear, the birds simply sing in echo of this Earth Song, for more info on Earth Song visit <A HREF=http://www.irobonix.com/>Irobonix (Aplied Organic Theology)</A>
They usually do it to call in birds to mate.
Some birds have a sweet chirp to their voice! :)
they sleeping silly!
They are looking for mates!
yes
Birds chirp when they sing. Birds begin with the letter b.
budgie, other birds :)