What's in Flight
May, 2019
Almost nightly between now and the end of May, millions upon millions of birds fly over Carl Schurz park and over the city. ‘After dark, if you stand outside [or on top of a tall building], you can often hear the “chip, chip, chip,” calls as they pass. And if you put your binoculars up you can see them flying across the moon,’ says birding expert and ecologist Gabriel Willow.
Scarlet Tanager Male
Deborah E Bifulco
New York City is on the Atlantic Flyway, one of the most important global migration routes, which runs from South America up to Greenland. It is used by dozens of species of birds, in particular tiny tropical songbirds, who fly north in spring to mate, nest and breed around the New York region, and further north in the Adirondacks, the boreal forests of Canada and beyond.
Baltimore Oriole Male
Deborah E Bifulco
During May, many of these colorful migrants stop to rest and recover in our park. ‘A lot of birds migrate by hugging the coastline. It is a landmark for them to follow, so green space beside the water is especially important,’ says Gabriel Willow, who on a recent May morning counted 43 species of birds in Carl Schurz’s trees including the magnificently colored Scarlet Tanager, Baltimore Oriole, Yellow Warbler, Black-and-white Warbler, Northern Parula, Hooded Warbler and Blue-headed Vireo. The birds are in their most dazzling plumage right now. The bright colors are eye candy for finding a mate.
Yellow Warbler Male
Deborah E Bifulco
‘It depends on the condition of the birds how long the stay around. If they are in decent condition, they will stop for a day or two to rest. A bird that got caught in a storm and has diminished energy may take a week to refuel,’ says Kyle Horton, a post-doctoral fellow at The Cornell Lab of Ornithology.
Black and White Warbler
Deborah E Bifulco
Favorite food stores for the birds in the park are the giant oak trees, which are in flower with long dangly yellow catkins and are abundantly provisioned with insects. A 2017 study by Doug Tallamy and Desiree Narango found that some oaks hold up to 534 species of moths and butterflies. They also report that other popular insect storehouses include Prunus (wild cherry and plum), Maple and Elm. The migrants tend to flit around in the uppermost branches. But sightings can occur at ground level too. In early May a pair of Barn Swallows with their signature forked tail, blue head and back and white belly were seen on the path next to Gracie Mansion, gathering supplies for a nest. Other migrants that may summer in the park include the beautiful little American Redstarts. The males are the most striking with their black plumage punctuated by patches of vibrant orange on their sides, wings and tail.
Blue-headed Vireo
Andy Reago & Chrissy McClarren
The sweet spot for seeing birds during the spring migration is from April 28-May 18, says Kyle Horton. ’Fifty percent of the birds move during just seven nights spread over three or four weeks.’ By tuning into the Doppler radars used to track weather, the Cornell Lab of Ornithology is able to show in real time the birds flying up the coast and over the city. ‘The radars are extremely sensitive. There’s probably not a bird that’s too small to detect. Butterflies and other insects also show up. But there are low flying birds we may not catch.’
Northern Parula
Russ Wigh
Anyone can watch in real time on birdcast.info as migrating birds flood across the US. It is an astonishing sight. At peak migration there is a nightly surge of billowing white (which indicates millions of birds) massing up the coast and over the city. You can either watch the activity live (it typically starts two hours after dusk, says Kyle) or you can have your morning coffee and click a chosen date to see what happened the night before, or even the week before.
Barn Swallow
Corine Bliek
American Redstart
Deborah E Bifulco
Why do migrating birds fly during the night? ‘The atmosphere is calmer. It is cooler. There are fewer predators around and it allows the birds to get to their breeding grounds quicker. They fly all night and forage during the day,’ says Kyle. How tiny birds can sustain this non-stop activity for several weeks, over journeys that span thousands of miles, is something of a mystery. Or at least it was until scientists discovered recently that migrating birds often engage in something called unihemispheric sleep while flying. When they close one eye, one hemisphere of the brain goes to sleep.
Hooded Warbler
Deborah E Bifulco
Words: Lucie Young
Images: Deborah E Bifulco, Andy Reago & Chrissy McClarren, Corine Bliek, Russ Wigh
Links: birdcast.info