To Sleep, Perchance to Sing
Do animals dream? What might they dream about? If you're a male zebra finch, you might dream of wooing a female finch. Although science has yet to fully probe the deep recesses of the male finch mind, it appears that something of that sort might be going on.
Neuroscientists Amish S. Dave and Daniel Margoliash of the University of Chicago have shown that sexually mature male zebra finches sing—silently—in their sleep (Science October 27, 2000). It turns out that single neurons in the forebrain song system of the sleeping birds display a pattern of activity that's only seen in the waking bird when it sings. Dave and Margoliash think that this neuronal activity is part of the learning process—the birds are rehearsing in their sleep by dreaming about singing.
Since the awake male zebra finch will sing when a female is presented, it seems natural to ask whether the male finch has an image in mind when he sings in his sleep. Margoliash won't speculate, but if human males are any indication we might imagine they dream of fetching female finches. It's either that or bird seed.
You can hear the song of the awake zebra finch at: http://www.williams.edu:803/Biology/ZFinch/zfsong.html —Michael Szpir