Richmond residents don't know why the purple martins have returned to the Shockoe Bottom neighborhood, but this year they've decided to celebrate.

The city will hold a "Gone to the Birds" festival on July 26, featuring everything from bird experts to bird-themed "purple martinis."

That's in contrast to last year, when the birds showed up by the thousands, sparking complaints by residents about their droppings.

City officials considered cutting down the trees where the birds roost, but held off, partly because the birds could become a tourist draw.

Mike Wilson, a bird expert at the College of William and Mary, said there are about 3,900 purple martins in the neighborhood now, and there could be 10,000 by the time the festival starts.