The birds know it is spring. Take a few minutes and walk into the preserve early in the morning. Pick a time when the community surrounding Gahagan is quiet. Sunday is great because there is no noise competition from the industrial park or the nearby schools, but most windless morning will work. Find a bench, close your eyes and listen. See how many different bird sounds you can hear.
Can't make it? Play the movie and listen to a sample. Sorry, it isn't like being there!