The birds have been gathering since June in a row of pear trees in the city's Shockoe Bottom area. They now total 14,000 birds.
Once scorned for the mess they made, the blackish-purple birds now have their own festival.
"Gone to the Birds" will be held Saturday as bartenders serve up "Purple Martinis," restaurants offer discounts of up to 20 percent and guides take birders on tours of this urban aviary.
It's a mystery why the largest member of the swallow family in North America has selected a row of 15 Bradford pear trees to spend its summers.
Most people don't care and just enjoy the show, which includes thousands of the birds returning each night to the roost.
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