Do Hawks Migrate? Hawk Migration Routes and Hot Spots

Which hawks migrate, and which stay home?

Hawks fall into three broad groups when it comes to migration:

• Long-distance migrants leave their breeding range completely. Broad-winged hawks fly 3,000–6,000 km (1,900–3,700 mi) to southern Mexico, Central America and northern South America. Swainson’s hawks travel up to about 11,400 km (7,100 mi) each way to the grasslands of Argentina, Uruguay and southern Brazil.
• Partial migrants have some populations that move and some that stay. The red-tailed hawk is a good example: most birds from Canada and Alaska head south for the winter, while most in the southern United States, Mexico and Central America never leave.
• Residents such as Harris’s hawks in the southwestern United States, and broad-winged hawks on Caribbean islands, stay in the same area all year.

Other birds of prey follow similar patterns. The osprey is a long-distance migrant on both sides of the Atlantic, with North American birds wintering in South America and European birds in West Africa; see where do ospreys migrate?. In Europe, common buzzards from Scandinavia and Russia move south, some as far as southern Africa, while buzzards in Britain and western Europe usually stay put.

Why do hawks migrate?

The main driver is food. Many hawks feed on frogs, snakes, insects and other animals that disappear in northern winters, or on rodents that are hard to catch under deep snow. Moving south lets them follow food supplies, then return north in spring to breed where long summer days and plentiful prey help them raise chicks. Our article why do birds migrate? covers the wider reasons.

How hawks travel: thermals and ridges

Hawks are built for soaring, not for long periods of flapping. Instead of powering their way south, they save energy by riding rising air:

• Thermals are columns of warm air that rise from sun-heated ground. A hawk circles inside a thermal to gain height, then glides off in the direction it wants to go, slowly losing height until it finds the next thermal.
• Ridge lift forms when wind hits a long hill or mountain ridge and is deflected upward. Hawks can glide for long distances along ridges such as the Appalachians with hardly a wingbeat.

Because thermals form only over land and only during the day, hawks migrate in daylight, usually from mid-morning to late afternoon, and avoid long sea crossings. Instead they follow coastlines and funnel through narrow land bridges and straits. Broad-winged hawks gather in thermals in groups called kettles, which can contain thousands of birds. Red-tailed hawks, by contrast, usually travel alone, waiting for days with favorable winds.

Famous hawk migration hot spots

Because hawks follow ridges, coasts and land bridges, huge numbers pass a few places that have become famous among birdwatchers:

• Hawk Mountain Sanctuary, Pennsylvania. Founded in 1934 by conservationist Rosalie Edge to stop the shooting of migrating hawks, it holds the world’s longest record of raptor migration counts. An average of about 20,000 hawks, eagles and falcons pass its lookouts each autumn.
• Veracruz River of Raptors, Mexico. The largest raptor migration counted anywhere: between four and six million birds pass each autumn, including nearly the entire world populations of broad-winged hawks, Swainson’s hawks and Mississippi kites.
• Hawk Ridge, Duluth, Minnesota. Hawks avoid crossing Lake Superior and follow its shore; up to about 15,000 red-tailed hawks have been counted here in one autumn.
• Derby Hill, New York. A spring site on Lake Ontario, where up to 19,000 red-tails have been counted in a season.
• Cape May, New Jersey, a coastal hot spot especially rich in falcons and smaller hawks.
• Europe and the Middle East: Falsterbo in Sweden, the Strait of Gibraltar, the Strait of Messina, the Bosphorus in Istanbul, Batumi in Georgia and Eilat in Israel all see hundreds of thousands of migrating raptors, especially honey buzzards and other buzzards.

When is the best time to see migrating hawks?

In North America, autumn migration runs from late August to early December. At Hawk Mountain, broad-winged hawks peak in mid-September, sharp-shinned hawks and ospreys in late September and early October, and red-tailed hawks from late October into November, followed by golden eagles. The best days often follow the passage of a cold front, when northwest winds push birds against the ridges.

Spring migration is more spread out, running from late February to May. Red-tailed hawks begin moving north early, with peak numbers in late March and early April. For tips on identifying the birds you see, try our hawks of North America guide.

Why hawk counts matter

Hawk watch counts are more than a hobby. Because the same sites have been counted for decades, the numbers show how raptor populations are changing. Hawk Mountain’s counts helped reveal the collapse of birds of prey during the DDT era and their later recovery, and today counts across North America and Europe track the effects of habitat loss and climate change on migrating hawks.