Golden Eagle Migration Explained

The migration patterns of golden eagles are somewhat confusing. Some populations of golden eagles in the west are migratory, while others are year-round residents. All golden eagles in the east are migratory. Eagles from the west and east have similar migration patterns.

• The golden eagle has migratory and non-migratory populations.
• Most eagles breeding in the northernmost part of its range are migratory
• Golden eagles migrate alone, following traditional routes
• Their wintering grounds overlap with that of year-round resident eagles
• Golden eagles generally return to the same breeding and wintering grounds
• All golden eagles in the east are migratory

Do golden eagles migrate?

The North American golden (Aquila chrysaetos canadensis) has its stronghold in western North America. A small population is found in eastern North America. However, golden eagles wander widely and can be found throughout Canada, the United States, and Northern Mexico in small numbers and as vagrants.

Some populations of golden eagles are migratory, while others are year-round residents.

All golden eagles perform random short, medium, and long-distance movements throughout their life cycles. 

However, migratory movements, defined as movements that predictably occur every year, are only performed by golden eagles breeding in the northernmost parts of the species’ range.

Migratory and non-migratory golden eagles 

Golden eagle biologists suggest that the approximate divide between the migratory and non-migratory golden eagle populations occurs approximately along latitude 55.

The approximate divide runs through middle British Columbia, Alberta, Saskatchewan, Quebec, and Newfoundland in Canada. 

Most golden eagles breeding north of latitude 55 migrate south. Birds that breed in the northernmost portion of the species range are considered obligate migrants. 

Non-migratory golden eagles

Golden eagles that breed south of latitude 55 tend to be year-round residents. The further south they breed, the more likely they are year-round residents. 

It is important to remember that latitude 55 degrees is only used as an approximate reference for dividing migratory and non-migratory golden eagle populations.

When do golden eagles migrate south?

Fall migration (North-South)

• Golden eagles in the west: Telemetry studies revealed that birds leave their wintering grounds over a broad period of time, from August through November. 
  
  Migratory eagles may be pushed out of their breeding grounds by a mid-October early heavy snowfall.
  
  Initiation of the Fall migration can vary based on the status of a bird. Individuals that failed to hold a breeding territory or had a failed nesting attempt begin their migration south earlier than those who successfully raised young. 
  
  In general, juveniles of the year begin migrating south between mid-September and early October.

• Golden eagles in the east: Telemetry studies of golden eagles in the east revealed that eagles nesting in Canada initiated their fall migration between August 11 through December 17.

Spring Migration (South-North)

• Golden eagles in the west: Adults individuals are the first to return to the wintering grounds, followed by young birds. Adults began migrating north from southeast Idaho between March 4 and April 13. 
  
  A long-term study found that adults departed the southwest region between early March and April

• Golden eagles in the east: Adult golden eagles in the east begin their spring migration between February 4 and April 13.
  
  Subadults birds leave the wintering grounds from February 14  to May 15.
  
  Juvenile birds are the last to depart, beginning their northbound journey from  March 22 to  May 10.

How long does the golden eagle migration journey last?

Migration time for migratory golden eagles varies depending on the distance between breeding and wintering grounds, the bird’s age/social status, and whether it is the spring or fall migration.

The Spring or northbound migration tends to be shorter and is initiated by breeding adults that rush back to claim suitable breeding territories. Juvenile and subadult individuals do not breed until their fourth year. They start their journey north later and take longer to reach the northern summer range.

According to a study that included adult and juvenile eagles, nonbreeding birds arrived at the same region up to 12 weeks after the adults.

The Fall or southbound migration period tends to last longer due to a lack of urgency to reach the wintering grounds.

• Duration of Fall migration in the west: Southbound eagles take between 6 and 47 days to reach their wintering grounds.
  
  Variations in distance between a bird’s breeding and wintering grounds explain the broad variation in time.

• Duration of Fall migration in the east: Adults took an average of 52 days while young birds took 56 days.
  
  Young eagles in the east regularly take stopovers that last several weeks before resuming migration.
  
  Southbound young eagles can take up to 153 days to reach their wintering grounds.

Spring migration

• Duration of Spring migration in the west: A study in Idaho found that adults leave between March 4 – and April 13. Juveniles left from April 6 through May 8.
  
  Eagles in this study took from 6 to 27 days to reach the breeding grounds.

• Duration of Spring migration in the East: Adult left the wintering ground between February 4 and April 13. Juveniles initiated the spring migration between February 14 through May 15.
  
  To reach the breeding grounds, adult golden eagles took an average of 29 days, subadults took 32 days, and juveniles took 37 days.

Do golden eagles return to the same wintering and breeding areas every year? 

Throughout its range, golden eagles exhibit variable breeding and nonbreeding site fidelity.

Adults typically migrate to and from the same wintering and breeding territory. Some mated pairs have returned for over 11 years to the same breeding territory.

But many individuals choose to breed and winter in different areas every two years.

Young birds try multiple breeding and wintering areas before settling in as adults. 

After wandering for their first three years, juvenile birds generally breed in the same general area where they were born.

Where do migratory golden eagles spend the winter?

Golden eagles in the west: Telemetry studies of golden have determined that the wintering range of migratory golden eagles extensively overlaps with the range of year-round resident eagles in western North America.

As a general rule, the further north a golden eagle breeds, the further south it winters. 

For instance, golden eagles that breed in northern Alaska, Yukon, and North West Territories, are known to undergo the longest migrations, wintering in Arizona, Colorado, New Mexico, Southern California, and Northern Mexico.

Eagles that breed further south, closer to the aforementioned population divide, migrate shorter distances to north and middle western North America. 

Eastern Eagles in the East: The stronghold of wintering golden eagles occurs in central Michigan, eastern West Virginia, northwestern Pennsylvania, and northeastern Alabama. However, there are other scattered localities where golden eagles spend the winter in small numbers.

Non-migratory eagles stay year-round in the same territory or general area. However, some birds perform medium and long-distance movements but generally return to the area from where they departed.

Distances covered by migratory golden eagles

The following are distances covered by migratory golden eagles to and from known breeding and wintering localities. These distances were obtained by following the path migratory eagles in the west and east follow during migration.

Golden Eagles in the West (miles)	Golden Eastern in the East (miles)
N. Alaska – C. Chichuahua (Mexico): 3,980	N. Quebec – SE Tennessee: 1,960
N, British Columbia – C. Nevada: 1,260	C. Quebec – C, West Virginia: 1,117

Golden eagle migratory routes 

Western and eastern populations migrate along mountain chains, taking advantage of the updrafts generated by the geography of the route. Soaring and gliding are effortless when the air is an updraft. 

Migration Routes in the west 

Telemetry studies and years of field observations have helped delineate the migrations routes of golden eagles in the west.

Golden breeding in Alaska, Yukon, the North West Territories, British Columbia, and Alberta fly either to the Pacific Coast Range or directly to the Rocky Mountains. 

Birds then follow along the Rocky Mountains to the south continuing to Wyoming. 

Some birds stay in regions adjacent to the mountain chain or disperse in other areas. Others continue south as far as Northern Mexico.

The migration route followed during the spring is similar. Birds returning from a wide wintering range tend to funnel towards the Rocky Mountain range to continue north. 

Birds drop out of the main route and fly to their breeding territories, while others continue up to the pacific range to disperse further north in Alaska. 

A small number of birds use alternative routes.

Migration Routes in the East

Eastern golden eagles migrating south in Fall follow a well-defined migration pattern through the Great Lakes and along the Appalachian Mountains. 

Birds breeding in a broad region follow specific routes to funnel and concentrate along the North Shore of the Gulf of Saint Lawerence and the Appalachian Mountains.

Eagles then follow along the Appalachian Mountain range to reach their wintering grounds.

Birds breeding in eastern Canada may migrate along the Atlantic coast and fly towards the Appalachian mountains. 

During spring migration, birds retrace their migratory route. Birds heading north follow the Appalachian and Allegheny mountain ranges. Further north, birds begin to take specific directions toward their breeding territories.

References:

• Bedrosian, B. E., R. Domenech, A. Shreading, M. M. Hayes, T. L. Booms, and C. R. Barger (2018). Migration corridors of adult Golden Eagles originating in northwestern North America. PLoS ONE 13(11): e0205204.
• Brodeur, S., R. Décarie, D. M. Bird, and M. Fuller (1996). Complete migration cycle of Golden Eagles breeding in northern Quebec. Condor 98(2): 293–299.
• Katzner, T. E., M. N. Kochert, K. Steenhof, C. L. McIntyre, E. H. Craig, and T. A. Miller (2020). Golden Eagle (Aquila chrysaetos), version 2.0. In Birds of the World (P. G. Rodewald and B. K. Keeney, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA.
• Omland, K. S., and S. W. Hoffman (1996). Seasonal, diel, and spatial dispersion patterns of Golden Eagle autumn migration in southwestern Montana. Condor 98: 633–636.
• Yates, R. E., B. R. McClelland, P. T. McClelland, C. H. Key, and R. E. Bennetts (2001). The influence of weather on Golden Eagle migration in northwestern Montana. Journal of Raptor Research 35(2): 81–90.