Ruby-throated hummingbirds should be in Chicago soon. View Full Caption Sarah Mayhew/Journey North

CHICAGO — Flying rubies will be entering the city limits any day now.

The ruby-throated hummingbird migrates through and sometimes nests in Chicago every year. The tiny buzzing birds will soon be found anywhere in Chicago that has good nesting deciduous trees like maples and an ample supply of nectar-producing flowers.

Of course, birders can try to get their attention with feeders holding a mixture of three parts water, one part sugar.

"They're a very adaptable bird to human environments," said Elizabeth Howard, founder and director of Vermont-based Journey North, a nonprofit site that tracks the hummingbirds' migration. "You should have them there this week or next."

Journey North allows registered users to submit hummingbird sightings on a map, which updates as the birds make their way north from Central America, Mexico and the southeastern portions of the U.S.

Here is the birds' live progress so far (with automatic updates):

Male hummingbirds — which have distinctive ruby-red throats — are the first to arrive to set up a breeding territory. The females follow about two weeks later. Howard said males try to mate with as many females as possible and don't help raising the young.

"The males are quite promiscuous," Howard said. "The females do all the work."

Hummingbirds' nests, made with spider webs and lichens, are only the size of a quarter or bottlecap. The eggs are only as big as jellybeans, Howard said.

They'll be in Chicago through the summer, Howard said.

"They're nesting; that's why they're here," Howard said.

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