call

 https://www.google.com/search?q=bird+call

Couple

http://ancientvoice.wikidot.com/mbh:mandapala
https://en.wikipedia.org/wiki/Jarita
http://www.sacred-texts.com/hin/m01/m01231.htm
https://www.youtube.com/results?search_query=saranga+birds

birdie

 https://www.google.com/search?q=birdie 

chirp

 https://www.google.com/search?q=chirp

trill

 https://www.google.com/search?q=trill

squawk

 https://www.google.com/search?q=squawk

twitcher

 https://www.google.com/search?q=twitcher