Quick answer
The American kestrel has an average lifespan of 5-7 years in the wild. Captive American kestrels can live up to 14 years or more.
Average lifespan in the wild
The American kestrel, also known as the sparrow hawk, is North America’s smallest and most common falcon. These small raptors have an average lifespan of 5-7 years in the wild according to banding data, though some individuals have been recorded living up to 12 years.
Factors that influence American kestrel lifespan in the wild include:
- Natural predators – American kestrels face threats from larger raptors like peregrine falcons, great horned owls, red-tailed hawks, and Cooper’s hawks. Mammalian predators like raccoons, snakes, and domestic cats may also prey on eggs and nestlings.
- Starvation – Harsh winters, droughts, or reduced prey populations can lead to starvation.
- Disease – American kestrels are susceptible to various bacterial, viral, fungal, and parasitic diseases like avian malaria, West Nile virus, aspergillosis, and nematodes.
- Collision hazards – Kestrels are vulnerable to death from collisions with vehicles, windows, towers, and other structures.
- Habitat loss – Destruction of the open habitats American kestrels prefer can lead to population declines and reduced lifespans.
On average, the annual survival rate for adult American kestrels is estimated to be around 60%. However, survival rates can vary significantly across different populations, seasons, and years. The highest mortality occurs within the first year of life when juveniles are still developing key survival skills like efficient hunting.
Maximum lifespan in captivity
Under human care in zoos, nature centers, breeder facilities, and as pets, American kestrels can live significantly longer than they do in the wild. The maximum recorded lifespan for captive American kestrels is 14 years and 11 months according to records kept by the US Geological Survey Bird Banding Lab. However, most captive kestrels live to around 10-12 years.
Key factors enabling the increased lifespan of captive American kestrels include:
- Consistent access to food and water
- Protection from predators and hazards
- Veterinary care and disease prevention
- Maintenance of climate-controlled housing
- Opportunity to reproduce
- Mental stimulation
With proper diet, housing, veterinary care, exercise, and enrichment, captive kestrels are able to live free from many environmental stressors they would face in the wild. Their average survival rate per year is significantly higher as a result.
Lifespan variations
While 5-7 years is the average lifespan for wild American kestrels and 10-14 years is typical in captivity, there are some key factors that can influence an individual kestrel’s longevity:
Sex
Female American kestrels tend to have higher survival rates than males. This may be partially due to the risks males face while competing for territories and mates during the breeding season.
Geographic location
Kestrels living at more southerly latitudes with milder climates may live longer than those inhabiting northern extremes of their range. Harsh winters likely take a toll on kestrel numbers and health in northern regions.
Migration
Migratory populations of kestrels face significant energy expenditure during migration flights twice per year. The long-distance travel, exposure to weather, and inconsistent food sources may negatively impact their annual survival rates compared to non-migratory populations.
Food availability
Kestrels are vulnerable when prey populations decline. Abundant food enables kestrels to maintain good body condition and avoid starvation risk, potentially increasing their lifespans.
Individual constitution
As with any species, some individual kestrels are genetically endowed with physiological traits that increase their resilience and enable them to live longer. These robust individuals are more likely to survive winter extremes, food shortages, disease outbreaks, and predation attempts.
Factors affecting lifespan in the wild
The average 5-7 year lifespan of wild American kestrels is influenced by a variety of environmental and biological factors. Here is an overview of some key elements that impact kestrel mortality and longevity in natural habitats.
Weather extremes
Harsh winters or summer droughts make it harder for kestrels to catch prey. Most kestrels migrate up to 500 miles south of their breeding territories to find food over winter. Those that do not migrate survive best in areas with abundant rodent populations that allow year-round hunting. Prolonged severe weather can lead to starvation and hypothermia.
Food availability
Kestrels primarily prey on small mammals like voles, mice, shrews, bats, and insects. Population crashes in rodent numbers can quickly lead to food scarcity and starvation risk. Some kestrels forage more broadly and are less impacted by vole population cycles.
Nest site competition
American kestrels nest in tree cavities or crevices in human structures like barns, sheds, and nest boxes. Competition for quality nest sites from introduced species like European starlings may limit kestrel breeding success and offspring survival.
Predation
Common kestrel predators include larger raptors, snakes, domestic cats, raccoons, and American crows. Nestlings and eggs are especially vulnerable. Adults may be attacked at bird feeders or taken by surprise during migration. Predation accounts for up to 26% of kestrel nest failures.
Collisions
As they scan for prey from perches and hover to hunt, kestrels are vulnerable to collision with vehicles and obstacles like fences, wires, turbines, tall buildings, and towers. Window strikes are another major hazard.
Disease
Parasites like nematodes, fungi, bacteria, and viruses can sicken and weaken kestrels. West Nile Virus has caused regional population declines. Careful use of pesticides reduces risk of poisoning.
Habitat loss
American kestrels thrive in open habitats with scattered perches and nesting cavities, like meadows, grasslands, pastures, agricultural areas, and suburban parks. Habitat loss and degradation reduce nest sites and hunting perches.
Lifespan in captivity
When kept in controlled captive conditions, American kestrels are able to live significantly longer than their wild counterparts, with average lifespans of 10-14 years and maximum lifespans reaching nearly 15 years. Here are some key factors enabling their longevity in captivity:
Consistent food
In zoos, nature centers, breeding facilities, and homes, kestrels are provided with a stable supply of food in the form of mice, chicks, or commercial bird of prey diets. This protects them from the risk of starvation.
Lack of predators
With no natural predators in controlled captive settings, kestrels are protected from risks like great horned owls and other raptors that might prey on them in the wild.
Veterinary care
Regular check-ups, preventative care, and treatment of injuries or disease by avian veterinarians helps minimize health issues that could shorten lifespans.
Controlled climate
Indoor housing protects captive kestrels from exposure to harsh weather extremes. Temperatures are kept at healthy levels year-round.
Breeding opportunity
The chance to breed and rear young provides mental stimulation that may promote well-being and longevity. Removal of eggs helps limit energy demands.
Mate choice
In zoos and conservation programs, mates can be selectively paired to maximize genetic diversity and offspring vigor rather than leaving pairing to chance.
Mental enrichment
Keepers use devices like puzzle feeders, balls, and training to provide physical and mental exercise resembling natural hunting behaviors. This staves off boredom.
With dedicated husbandry, captive kestrels thrive well beyond the averages seen in the stressors of the wild. Careful management is key to ensuring maximum lifespans.
Record lifespans
While 5-7 years is typical in the wild, and 10-14 years common in captivity, a few exceptional American kestrels have managed to live even longer. Here are some record ages:
- The oldest known wild American kestrel was a 12 year old female banded in New Jersey.
- The oldest captive kestrel was a female that lived 14 years and 11 months at the Philadelphia Zoo.
- A European zoo kestrel lived 13 years and 3 months per longevity records.
- Several private aviculturists have reportedly had captive kestrels reach 15-16 years.
These record ages are well beyond average for the species, but illustrate that under highly favorable conditions, American kestrels can live significantly longer than their typical 5-7 year natural lifespans. Exactly why some individuals so dramatically outlive their peers remains a mystery. Genetics, husbandry, and luck may all play a role.
Lifespan differences from related falcons
The American kestrel’s average lifespan of 5-7 years in the wild is on the lower end of lifespans seen in related falcons around the world. Here’s how it compares to a few relatives:
Species | Average wild lifespan |
---|---|
American kestrel | 5-7 years |
Eurasian kestrel | 6-8 years |
Merlin | 5-15 years |
Peregrine falcon | 10-15 years |
Gyrfalcon | 10-15 years |
Prairie falcon | 5-10 years |
The American kestrel is a smaller, shorter-lived species adapted to chase small prey in open areas. Larger relatives that take birds on the wing like merlins and peregrines have longer average natural lifespans. But the American kestrel’s smaller size does enable it to thrive in more varied habitats across North America.
Conclusions
In summary, the American kestrel is a small falcon with an average lifespan of just 5-7 years in the wild. This short-lived raptor faces many threats from predation, starvation, disease, and collisions in nature. However, in captivity, American kestrels are capable of living up to 14 years or more with proper care, food, and protection from dangers. Though the kestrel’s lifespan is on the low end for falcons, it is well adapted to its niche preying on small mammals and insects across a diversity of open habitats. With conservation efforts to preserve the habitats and prey sources kestrels rely on, we can ensure healthy wild populations persistent across North America for generations to come.