The rare sighting of a tiny yellow songbird this week gave hundreds of enthusiastic birders in Central Park something to tweet about.
"We don't get many [birds like this] so it's always very exciting," said avid birder Starr Saphir as she spied a lone prothonotary warbler by the Ramble during one of her daily early morning bird walks.
The flamboyant songbird - with blue-gray wings and tail covering a yellow belly - is among the thousands of birds making a pit stop at city parks and marshes throughout the month during their annual spring migration.
Hundreds of species of colorful birds will soar above the city and sing from the treetops as they make their way from South America to breeding grounds in the north.
Some stay for a night or two, some stay longer.
Earlier this week, naturalist and educator Gabriel Willow spotted one of his favorite birds, an American woodcock, as it hunkered down on vegetation near the Mid-Manhattan Library in Bryant Park. But the next day, the shorebird was gone.
"It was probably hunting for earthworms, and wondering where it was," said Willow, who leads free bird-watching tours for the NYC Audubon and other local bird groups.
The urban jungle is a natural attraction for birds who travel thousands of miles over water down two migratory flyways along the coast. The trip is arduous, and lush greenery in the parks and marshes lures them in, offering a rich bounty of insects, buds and seeds to feed on.
"Take a lunch break and look up," suggested Willow, who also co-created an iPhone app that tracks bird sightings available at www.thewildlab.org.
In Central Park, the varied habitats of the north end and the Ramble offer the top places to spot birds, among them hummingbirds and orioles feeding on trees, and thrushes that "sing ethereal songs from dawn to dusk," Willow said.
Brooklyn's Prospect Park has one of the city's largest populations of spring migratory birds. Also, the Jamaica Bay Wildlife Refuge is a prime birding spot for thousands of shorebirds, waders, waterfowl and dozens of migratory songbirds that feast on the eggs of the horseshoe crab during its mating season.
Still, migration can be risky. The trip is not only exhausting, but the birds travel over unfamiliar territory, and have to endure natural and manmade threats along the way.
Backyard cats, power lines and windows pose the greatest threats - and many birds die en route.
The ever-expanding skyline also makes the journey difficult.
"The city's erection of glass buildings makes it a challenging passage and many birds collide or get confused and crash," said Rita McMahon, a wildlife rehabilitator who runs the Wild Bird Fund (wildbirdfund.org), which last year treated more than 1,000 injured birds.
New York is the only top 10 U.S. city without a dedicated wildlife rehabilitation center. Therefore, injured birds are treated at Animal General, a veterinary hospital on the upper West Side, and in McMahon's home.
McMahon and other wildlife rehabbers, however, are working hard to get funding and support to establish an independent center.
Those who find an injured bird should place it in a dark box and call the Wild Bird Fund at (646) 306-2862 or find a local rehabber at www.nyswrc.org.
For a list of birdwalking walks, bird-a-thons and bird events, go to New York City Audubon at www.nycaudubon.org.