Observation Deck Now Open

I played recorder for the Sandhill Cranes today.
They could have flown away, 
They were not, after all, a captive audience.
They chose to stay,
Curious they were, showing no fear.
Necks stretched long, heads turned to hear
They stirred nary a bit as I drew near.

Perhaps they understood I was the captive, 
Held back by the observation fence.