Turkey vultures are a common sight in many parts of North America, circling lazily on thermals as they search for carrion. But as winter approaches and temperatures start to drop, turkey vultures disappear from many northern areas. This seasonal absence prompts an obvious question: do turkey vultures migrate south for the winter?
Quick Answer
The quick answer is yes, turkey vultures do generally migrate south in the winter. However, their migratory patterns are quite complex and depend on a number of factors. While some turkey vulture populations are fully migratory, others are partially migratory or even non-migratory. The exact migratory behavior depends on the subspecies, location, food availability and weather conditions.
Why Do Birds Migrate?
Before looking at the specifics of turkey vulture migration, it helps to understand why birds migrate in general. Migration is an adaptation that allows birds to take advantage of seasonal food resources and weather conditions. The main drivers of migration include:
- Food availability – Birds migrate to areas where food is more abundant at different times of year.
- Nesting habitat – Birds migrate to areas with suitable nesting habitat during breeding season.
- Weather – Birds avoid extreme cold in winter or heat in summer by migrating.
- Length of daylight – The long days of northern summers stimulate breeding behavior.
For turkey vultures, food availability and weather are likely the main factors influencing any migratory movements. Vultures need reliable food sources and avoid cold winter temperatures.
Turkey Vulture Migration Patterns
There are five subspecies of turkey vulture in North America:
- Cathartes aura aura – Eastern turkey vulture
- Cathartes aura meridionalis – Southeastern turkey vulture
- Cathartes aura septentrionalis – Western turkey vulture
- Cathartes aura falklandica – Southern South American turkey vulture
- Cathartes aura jota – Northern South American turkey vulture
Their migration habits vary considerably:
Eastern turkey vulture
The eastern turkey vulture (Cathartes aura aura) is fully migratory, traveling south for the winter. Banded birds in this subspecies have been recovered hundreds of miles south of where they were tagged during summer.
Migration distances tend to increase further inland and at higher latitudes. Eastern vultures that breed in Canada may migrate as far south as South America. The birds follow major mountain ranges, coastlines and river corridors during migration.
Southeastern turkey vulture
Southeastern turkey vultures (Cathartes aura meridionalis) are partially migratory. Some populations may remain resident year-round, while others migrate short distances.
Banded birds have been recovered up to a few hundred miles north or south of their tagging sites. Migratory tendencies depend on food availability. If food is plentiful, the birds are less likely to migrate.
Western turkey vulture
The western turkey vulture (Cathartes aura septentrionalis) displays variable migratory behavior across its range. Populations in the Northwest may migrate south in winter, while those further south are often resident.
Some western vultures perform altitudinal migration, moving to lower elevations in winter rather than making a long southward journey. Their migration habits are quite flexible depending on local conditions.
Turkey Vulture Subspecies | Migration Habits |
---|---|
Eastern turkey vulture | Fully migratory |
Southeastern turkey vulture | Partially migratory |
Western turkey vulture | Variable migratory behavior |
Factors Influencing Turkey Vulture Migration
As the above summaries demonstrate, turkey vulture migratory patterns are quite complex. Their migration is influenced by a combination of factors, including:
Food Availability
Access to food is a primary driver of turkey vulture movements. In winter, carrion food sources become scarcer at higher latitudes as many prey animals migrate or enter hibernation. Lack of food motivates turkey vultures to migrate south.
Mild winters may allow northern populations to overwinter if food is adequate. And supplemental food sources from humans, like roadkill or livestock operations, may also support overwintering.
Weather
Freezing temperatures and snow limit the ability of turkey vultures to find carrion. Their largely featherless heads also make them vulnerable to cold.
To avoid frigid winter conditions, most vultures migrate south out of northern areas. Dropping temperatures provide an important trigger for migration in the fall.
However, vultures can withstand some cold. For example, populations in mild coastal and urban areas may not migrate.
Subspecies
As explained earlier, the different turkey vulture subspecies show varying degrees of migratory tendency. The eastern subspecies is highly migratory, while the southeastern subspecies is partially migratory. The western vulture displays great flexibility.
These variations arise from evolutionary adaptations to the environments each subspecies occupies. The migratory eastern vulture likely evolved in harsh northern climates, for example.
Geography
Turkey vultures that breed at higher latitudes and northern inland areas are more likely to migrate greater distances. Birds further south migrate shorter distances or not at all.
Coastal populations also tend to be less migratory than inland ones at the same latitude. Coastal areas have more moderate winters and access to food from the ocean.
Age
Younger turkey vultures are more likely to migrate than older birds. One Florida study found that adult vultures exhibited year-round residency, while younger vultures migrated north in spring and south in fall.
With age comes experience, and older vultures may be better adapted to finding food and withstanding local conditions in winter.
turkey vulture Wintering Areas
During migration, turkey vultures from northern areas fan out across a broad swath of southern North America. Their winter range extends from southern Canada south across the southern United States and Mexico into Central and South America.
Some specific wintering regions include:
- Southern coasts of the U.S. – California, Texas, Florida
- Southwestern U.S. and northwest Mexico
- Southern Mexico
- Central America
- Northern South America
Coastal areas, such as Florida and California, attract large numbers of overwintering vultures. Their mild climates and abundant food sources allow the birds to persist year-round.
Further south, seasonal movements become elevation migrations rather than long journeys north and south. Vultures move downslope in winter and upslope in summer.
Roosting Behavior
A notable aspect of turkey vulture wintering behavior is their congregation into large communal roosts at night. These roosts can contain thousands of vultures settling together in trees or on the ground.
Possible benefits of communal roosting include:
- Thermoregulation – Huddling together may help retain heat.
- Social interaction – Information is shared about food sources.
- Predator protection – More eyes and beaks to deter predators.
Major turkey vulture roosts occur in areas like Florida, Texas and southern California during winter.
Southward Migration
As fall approaches, migratory turkey vultures begin drifting south. The timing of migration depends on a number factors:
- Weather – Coldest temperatures trigger departure.
- Age – Adults and juveniles may migrate at different times.
- Subspecies – Migration timing is genetically programmed.
- Region – Northern birds migrate sooner.
In Canada, southbound migration may begin as early as August. Further south, it starts in September and October. Juveniles often migrate before adults.
Migrating flocks follow mountain ridges, coastlines and river corridors. They travel during the day when thermals provide lift, and roost communally at night.
It appears turkey vultures rely on innate navigation ability to find their wintering sites, rather than specific learned routes. Some vultures cover over 4,000 miles during fall migration.
Northward Migration
The return north in spring generally occurs earlier than the fall migration. In the southern U.S., northbound vultures may appear as early as February. Further north, they arrive in March and April.
Adults typically migrate before younger birds again. Traveling singly or in small flocks, the vultures ride spring thermals and updrafts to make rapid progress.
Upon arrival on the breeding grounds, turkey vultures reunite with old mates or establish new bonds. They refurbish old nests or build new ones in preparation for egg laying in April to June.
Threats During Migration
Turkey vultures face a number of natural and human-caused threats during migration:
- Adverse weather – Storms or strong winds can blow migrating vultures off course and force them to land.
- Habitat loss – Development destroys the vultures’ migratory corridors.
- Wind turbines – Vultures can collide with wind turbines while soaring.
- Vehicle strikes – Vultures feeding on roadkill are vulnerable to collision with vehicles.
- Illegal shooting – Some people illegally shoot turkey vultures.
- Poisoning – Vultures can ingest poisoned bait left out to kill other animals.
Conservation measures aimed at protecting migratory habitat and reducing mortality threats are important for ensuring healthy turkey vulture populations.
Unique Aspects of Turkey Vulture Migration
While many birds embark on spectacular migrations each year, turkey vultures have some distinctive migration characteristics:
- They rely on soaring flight to travel long distances.
- They migrate during the day and roost communally at night.
- They take a broad front approach rather than following narrow flyways.
- They display diverse migration strategies depending on location.
- Young birds often migrate separately from adults.
- They find their way using innate navigation, not learned routes.
These adaptations reflect the turkey vulture’s scavenging lifestyle and relationship to environmental conditions like wind and temperature. Their flexible migration strategies also enable them to persist across diverse habitats.
Conclusion
In summary, most turkey vulture populations migrate south to some degree in winter, but their migration patterns vary considerably. A number of factors influence migratory behavior, including food availability, weather, age, location and subspecies. Southern coastal regions attract large numbers of wintering vultures.
The timing of migration depends on conditions but generally occurs in autumn as temperatures drop and again in early spring. Although they face threats during migration, unique adaptations help turkey vultures complete their epic seasonal journeys across North America.