Aerial odysseys: bird migration in the Americas

The Atlantic Flyway follows the eastern regions of the Americas, from the Labrador Sea to the Appalachian Mountains, Caribbean Sea, and Amazon basin. Many migrants traveling from Canada and the United States shorten their route to South America by crossing the Atlantic Ocean in impressive multi-day non-stop flights.

Example Atlantic migrant: American Golden-Plover

The individual plover whose route is plotted on this map was captured in the National Petroleum Reserve in Alaska before flying across the Canadian far north. ¹  The plover made a multi-day non-stop crossing of the Atlantic Ocean before flying across Brazil, ending up in Argentina where it spent the northern winter. 

The Mississippi Flyway includes Hudson Bay, the Great Lakes, Mississippi River basin, Gulf of Mexico, and interior South America's upper Amazon basin. Many of the migrants in this flyway make non-stop flights across the Gulf of Mexico between North and Central America.

Example Mississippi migrant: Tree Swallow

While Tree Swallows migrate broadly across the North American continent, this individual started its journey near Edmonton, Alberta, and flew the length of the Mississippi River Basin before crossing the Gulf of Mexico to its winter grounds in Honduras. ² 

The Central Flyway runs the length of the Rocky Mountains, Central America, and the eastern Andes Mountains, connecting places as far away as Alaska and the Great Plains in the north with Argentina in the south. Migrants pass by the millions through migration bottlenecks in Mexico, Costa Rica, and Panama.

Example Central migrant: Swainson's Hawk

This hawk's migration connects grasslands in the United States to those of South America. This individual, which we profile in greater detail below, spent the summer in Idaho before flying south via the River of Raptors in Mexico to spend the northern winter on the Pampas of Argentina. ³ 

Diego arrived in north Texas in early September, and paused to fuel up for the long southward migration. Diego and other Swainson's Hawks often make stopovers at agricultural fields where they feed on grasshoppers and form large flocks to begin their migration to South America.

As Diego migrated across central Texas, he passed several wind farm developments. He flew close to additional wind farms in south Texas and, later in the year, near Managua, Nicaragua. Wind energy is an important resource for reducing the greenhouse gas emissions that drive climate change. By identifying the important places for birds and the latest technology to prevent mortality from collisions, we can build a clean energy future that protects birds and the places they need.

 View the tracks of dozens of other Swainson's Hawks in the Bird Migration Explorer. 

As Diego continued southward into Mexico and toward the Isthmus of Panama, the narrowing geography caused his path to converge with millions of other migrating hawks into a swirling "River of Raptors."  Some 4 to 6 million raptors crowd the skies above  Veracruz.

Each year from late August to late November,  ProNatura Veracruz  coordinates volunteers to count the number and species of migrating birds passing by in an effort to protect migratory raptors. Monitoring began over 30 years ago in collaboration with partners at  Hawk Mountain Sanctuary  and  Hawk Watch International . The Veracruz River of Raptors Project operates three programs: counting, banding, and environmental education.

Veracruz is a very important place in the world and a must-see for raptor and migrant bird lovers. ProNatura’s research has found that along with  Kéköldi  in Costa Rica and Cerro Ancon in Panama, Veracruz ranks among only five sites worldwide where more than a million migrating raptors pass during migration.

During the height of migration season—between early October and mid-November in Panama—Panama City's Tocumen Airport issues an alert to all planes regarding raptor migration. 

 Audubon Panamaʼs program —Raptors from Ocean to Ocean—monitors 15 species of migratory birds of prey that fly over the summit of Cerro Ancon in Panama City. Among the most common migratory species is the Swainson's Hawk, with Diego as one of nearly a million birds of this species passing by this site each year.

Colombia is the sole point of entry into South America for Diego and his fellow Swainson's Hawks. The country provides food, shelter, and roosting sites for large groups of migratory raptors before they disperse throughout their southern ranges. One critical migration corridor and roosting site for Swainson’s Hawks and Broad-winged Hawks is located in Tolima, central Colombia, where large flocks rest before continuing their migration along the Andes. 

Colombian biologist Esther Vallejo (Director of  Trópicos Colombia ) has been counting raptors for years in a quest to uncover a mystery: What happens to buteos—the group of birds that includes Swainson's Hawks—after they reach Colombia?

 Her work counting raptors  near Tolima is pioneering—between North and Central America there are more than 30 counting sites, but for South America there are three currently active sites, two for Colombia and one for Venezuela. A recent count at Tolima reached more than 700,000 individuals, positioning the count site as potentially the fourth most important site in the Neotropical region.

Trópicos works with communities in Tolima, conducting workshops with students and farmers to help them understand that raptors are not a threat to local livestock, and that they should be protected, not persecuted. Community participation is fundamental, and education is a key element in achieving a change in the local perception of these birds, which know no borders and help maintain the balance of ecosystems throughout the continent.

 See how the Tolima count site connects places across the hemisphere using the Bird Migration Explorer. 

Protected grassland areas account for less than two percent of the Pampas region, with the remainder owned and managed by private landowners. Recent years have seen a growing awareness among governments, NGOs, landowners, and scientists of the value of grasslands. As a result, efforts have been made to support ranchers and the production of natural grass-fed beef as an important strategy for keeping ranchers ranching and to maintain grasslands in a relatively natural state.

 BirdLife International , together with its national partners in the Americas— Aves Argentinas ,  Aves Uruguay ,  SAVE Brasil,  and  Guyra Paraguay —has developed the Southern Cone Ranchers Alliance (SCA), which targets conservation across 100 million hectares of native Pampas grasslands. Over 600 ranchers are members of the alliance, and already 300 ranchers have earned an "Alianza de Pastizal" beef certificate for their commitment to protecting the region’s grasslands and their biodiversity. Without ranchers, the remaining native Pampas will likely be converted to crop monocultures over the next century, with a consequent loss of wildlife.