MadSci Network: Zoology |
This is somewhat difficult to answer as it need not necessarily be migraton. The birds migt just be going back to their nests or for roosting. What you can do is watch at dawn if these birds come back or not. That might provide more insigts and for further details you may contact a local birdwatching club. Also let me know about your observations. I shall try my best to help you. My email id's are ankur_shah@indiatimes.com, naturalankur@rediffmail.com.
Try the links in the MadSci Library for more information on Zoology.