Do Falcons Migrate?

Around the 26th of September each autumn, something happens at Cape May Point, New Jersey. The peninsula juts into Delaware Bay and the Atlantic, and for two weeks it acts as a funnel. Peregrine falcons pile up at the tip, some days by the hundreds, before committing to the water crossing south. New Jersey Audubon’s hawkwatch records show that about 90 percent of the season’s peregrines pass Cape May between September 26 and October 12. The 2018 season counted 1,520 peregrines - the second highest total in the hawkwatch’s history. The rest of the year the site is quiet. This is what falcon migration looks like when it happens: concentrated, coastal, precisely timed.

But not every falcon does this. The question “do falcons migrate?” has a frustratingly honest answer - it depends entirely on which falcon and where it was born.

Three subspecies, three different answers

The peregrine falcon (Falco peregrinus) shows the full range of possibilities within a single species. North America has three subspecies, and each has a different relationship with migration.

F. p. tundrius, the tundra peregrine, breeds north of the treeline across northern Alaska, northern Canada, and Greenland. It is one of the longest-distance migrants in North America. Cornell’s All About Birds records that tundra-nesting falcons winter in South America and may cover 25,000 km (15,500 miles) in a year. A 1994 satellite-tracking study at Rankin Inlet, Nunavut tracked four falcons: three of them flew to southern Brazil, averaging around 8,900 miles on the southbound leg alone. A separate individual banded in the Northwest Territories was recovered 14,500 km south in Chaco, Argentina, under four months later. The Audubon Field Guide on peregrine falcons notes that migrants regularly follow coastal routes and occur well out to sea. Daily travel averages around 100 miles, with favorable conditions allowing up to 200.

F. p. anatum, the continental peregrine, breeds from the Alaskan taiga through most of North America and into Mexico. Whether any individual migrates depends on what its food does. Birds at northern latitudes follow their prey - shorebirds, waterfowl, songbirds - south when those species depart. Urban anatum peregrines nesting on bridge pylons and skyscrapers, where pigeons and starlings are available year-round, largely stay put. Both descriptions are accurate, of different birds in different cities.

F. p. pealei, Peale’s peregrine, occupies the coastline from the Aleutian Islands through southeastern Alaska. It is a resident. The marine environment provides seabirds and shorebirds through winter, and the subspecies does not typically migrate. It is highly specialized, hunting over open ocean using low-altitude technique that the other subspecies rarely employ.

The name “peregrine” comes from the Latin peregrinus, meaning wanderer. The species contains one of the longest migrations of any North American bird - and one of its most committed homebodies. Both facts apply to Falco peregrinus.

What the other falcons do

North America has four other regularly occurring falcon species, and none of them migrates quite like the tundra peregrine.

The merlin (Falco columbarius) has three North American subspecies with notably different habits. The taiga form migrates broadly, with some birds reaching South America. The Pacific Northwest race (suckleyi) is mostly resident year-round. The prairie race (richardsonii) has increasingly settled in northern plains cities - where House Sparrows provide a reliable winter food supply - and the Audubon Field Guide notes that since around 1960, some prairie merlins have stopped migrating in response to this urban resource. The species’ North American population is estimated at 3.2 million, classified as Least Concern by the IUCN.

The American kestrel (Falco sparverius) demonstrates a clean latitudinal pattern: northern populations migrate, southern ones do not. Most wintering kestrels remain in the southern United States, with a smaller number reaching Central America. Cornell Lab documents an unusual sex-based split in winter habitat - females tend to hold open grassland territories, while males are displaced into areas with more tree cover, apparently because females migrate south first and claim the better ground. Cape May recorded 5,406 kestrels on a single day in October 2018, the highest one-day count in the hawkwatch’s history, which illustrates how a seemingly familiar bird can concentrate in startling numbers during migration.

The prairie falcon (Falco mexicanus), a bird of western grasslands and desert scrub, is the least migratory of the group. The Audubon Field Guide states that many adults may be permanent residents near their nesting sites. Others make short shifts south or east onto the Great Plains after breeding, following the flocking Horned Larks and Western Meadowlarks that make up most of their winter diet. Its global population stands at roughly 110,000 birds, classified as Least Concern. It is not a long-distance migrant.

The leap-frog rule

One pattern cuts across all these species: birds that breed farthest north tend to winter farthest south, leapfrogging over populations that stopped migrating at more temperate latitudes. A tundra peregrine from Greenland does not stop in Georgia. It continues to Argentina. A peregrine from Maryland may travel no farther than the Florida coast. The same tendency appears in kestrels - Canadian birds push further south than birds from Kansas.

This is a consequence of competition more than climate. If mid-latitude wintering grounds are already occupied by resident and partial-migrant birds, the long-distance traveler has to continue south to find open territory. The distance any individual migrates is partly a function of how crowded the closer options already are. Understanding this pattern also explains something visible in backyard birds like the cardinal - sedentary, year-round populations tend to develop extremely strong site fidelity because the space is worth defending.

What Cape May shows

A hawk watch like Cape May or Hawk Mountain Sanctuary in Pennsylvania gives this biology a visible form. During peak migration weeks at Cape May, the peregrines are moving in compressed pulses tied to weather systems - a northwest wind after a cold front pushes the birds hard. But each one arrives independently. Peregrines do not flock or travel together. When dozens appear on the same afternoon, it is because the geography and the conditions funnel them to the same point, not because they organized it. They are coinciding, not cooperating.

The coastal route makes sense because it tracks the concentration of shorebirds and waterfowl along the Atlantic flyway - the same prey the bird depended on all summer is strung out along the coast heading south, and the peregrine follows the food column. Cleaning your feeders to bring in birds like hummingbirds follows the same logic: food drives presence, and presence drives movement. The same prey-tracking instinct shapes whether hummingbirds migrate or stay through winter.

The 1,520 peregrines at Cape May in 2018 were almost all F. p. tundrius - birds hatched somewhere above the Arctic Circle, navigating thousands of miles of coastline they had never seen before, burning stored fat over the open water crossing into Delaware. Most of them kept going. By November, some were in Argentina. The bridge peregrines in Chicago were watching pigeons.