The neo-tropical migrants (song birds that winter in the tropics) will return starting in mid-April and fill the New England woods straight through until the end of May. Preparing for this fleeting invasion of little, brightly colored birds is one of the great bird watching traditions. The key to finding the myriad of warblers, thrush, vireos, and buntings that will soon fill New England with color and noise is learning what to listen for. Seeing these small, agile birds moving through newly opened leaves is tough, and is only possible by learning each bird's song. There are dozens of species that will find their way to New England and learning all them can be daunting. The key is repetition and a head start. So brew some coffee, turn off the television, and prepare for an old-fashion cram session. For the next few weeks the Daily Bird New England will give up glossy photos, glib humor, and poetic meanderings for hard noise, crib notes: one day, one bird, one song. There will be no images, no life history, just a name and sound, and a few pneumonic devices to remember it by. The progression of species should naturally scaffold learning on the previous bird. Weekends of course are still for fun. Get ready to cram.