Spring migration brings millions of birds across American skies
Alona Yadav | Mar 12, 2025, 00:27 IST
( Image credit : Agencies )
The spring bird migration is in full swing across the US, with millions of birds flying at night. Cornell University's BirdCast technology tracks this phenomenon, highlighting peak migratory activity in several states. Conservationists urge turning off lights during peak migration to protect birds.
The annual spring bird migration is now in full swing across America, with radar tracking revealing a spectacular natural phenomenon happening largely unseen in the night skies.
"The movements are massive," explains Andrew Farnsworth, a migration ecologist at Cornell University. "On a big night in the spring, you're talking 450 to 500 million birds flying under cover of darkness."
This massive movement of birds occurs as species return to their summer feeding grounds, with spring migration officially running between March 1 and June 15. Currently, significant bird activity is being observed in Florida, the Southeastern United States, and parts of the Midwest.
Early migrants include ruby-crowned kinglets, swamp sparrows, and eastern phoebes moving northward from their southeastern winter homes. Meanwhile, Kansas and similar areas are seeing waterfowl, fox sparrows, American tree sparrows, dark-eyed juncos, red-winged blackbirds, and common grackles on the move.
Bird enthusiasts can follow this remarkable journey through Cornell University's BirdCast Migration Dashboard, which provides daily summaries of radar-based nocturnal bird migration. The system uses radar technology because most species migrate at night, some flying as high as 15,000 feet.
While migration is already underway, the peak is yet to come. "It's not until April that you really start to get the big bang of bird diversity," Farnsworth notes. "The peak migration comes like a wave across the United States, breaking from south to north."
Currently, migration numbers are especially high in New Mexico, Texas, Oklahoma, and parts of the Maryland-New Jersey region. For example, on a single night in March, an estimated 158,700 birds crossed Des Moines County, Iowa, including snow geese, dark-eyed juncos, killdeers, white-throated sparrows, yellow-bellied sapsuckers, northern shovelers, and buffleheads.
Birds migrate for various reasons, primarily to follow food sources. In North America, birds typically fly south for winter when food becomes scarce during colder months, then return north in spring to take advantage of growing insect populations, budding plants, and ideal nesting locations.
Migration patterns vary widely among species. Some birds are permanent residents that rarely migrate, while others make altitudinal shifts rather than geographic ones. Short and medium-distance migrants might travel a few hundred miles, while long-distance travelers like the blackpoll warbler can journey from Alaska to the Amazon, covering up to 8,000 miles.
Scientists are still unraveling exactly how birds navigate these impressive journeys. Research indicates they use multiple navigational tools, including day length, smell, the position of the sun and stars, and even the Earth's magnetic field.
Climate change presents challenges for migrating birds, as shifting plant budding and insect availability times can disrupt traditional migration patterns, leaving birds out of sync with their food sources precisely when they need nourishment for breeding.
To help these travelers, ornithologists recommend turning off non-essential lighting from 11 p.m. to 6 a.m. during peak migration periods, as bright lights can disorient night-flying birds and cause fatal collisions with buildings.
"These simple steps can help protect them," Farnsworth emphasizes. "And please make sure any glass in your house is bird friendly."
"The movements are massive," explains Andrew Farnsworth, a migration ecologist at Cornell University. "On a big night in the spring, you're talking 450 to 500 million birds flying under cover of darkness."
This massive movement of birds occurs as species return to their summer feeding grounds, with spring migration officially running between March 1 and June 15. Currently, significant bird activity is being observed in Florida, the Southeastern United States, and parts of the Midwest.
Early migrants include ruby-crowned kinglets, swamp sparrows, and eastern phoebes moving northward from their southeastern winter homes. Meanwhile, Kansas and similar areas are seeing waterfowl, fox sparrows, American tree sparrows, dark-eyed juncos, red-winged blackbirds, and common grackles on the move.
Bird enthusiasts can follow this remarkable journey through Cornell University's BirdCast Migration Dashboard, which provides daily summaries of radar-based nocturnal bird migration. The system uses radar technology because most species migrate at night, some flying as high as 15,000 feet.
While migration is already underway, the peak is yet to come. "It's not until April that you really start to get the big bang of bird diversity," Farnsworth notes. "The peak migration comes like a wave across the United States, breaking from south to north."
Currently, migration numbers are especially high in New Mexico, Texas, Oklahoma, and parts of the Maryland-New Jersey region. For example, on a single night in March, an estimated 158,700 birds crossed Des Moines County, Iowa, including snow geese, dark-eyed juncos, killdeers, white-throated sparrows, yellow-bellied sapsuckers, northern shovelers, and buffleheads.
Birds migrate for various reasons, primarily to follow food sources. In North America, birds typically fly south for winter when food becomes scarce during colder months, then return north in spring to take advantage of growing insect populations, budding plants, and ideal nesting locations.
Migration patterns vary widely among species. Some birds are permanent residents that rarely migrate, while others make altitudinal shifts rather than geographic ones. Short and medium-distance migrants might travel a few hundred miles, while long-distance travelers like the blackpoll warbler can journey from Alaska to the Amazon, covering up to 8,000 miles.
Scientists are still unraveling exactly how birds navigate these impressive journeys. Research indicates they use multiple navigational tools, including day length, smell, the position of the sun and stars, and even the Earth's magnetic field.
Climate change presents challenges for migrating birds, as shifting plant budding and insect availability times can disrupt traditional migration patterns, leaving birds out of sync with their food sources precisely when they need nourishment for breeding.
To help these travelers, ornithologists recommend turning off non-essential lighting from 11 p.m. to 6 a.m. during peak migration periods, as bright lights can disorient night-flying birds and cause fatal collisions with buildings.
"These simple steps can help protect them," Farnsworth emphasizes. "And please make sure any glass in your house is bird friendly."