Quick Answer
American Kestrels can and do eat squirrels, but squirrels are not a major part of their diet. Kestrels are small falcons that primarily eat insects, small mammals, and birds. They will opportunistically prey on squirrels, especially young squirrels, but have difficulty killing adult squirrels due to the size difference. Kestrels use their speed and agility to catch squirrels off guard, but it takes considerable energy and carries risk of injury. Overall, squirrels make up a very small percentage of the American Kestrel’s diet compared to easier prey like mice, voles, and large insects.
Diet of the American Kestrel
The American Kestrel (Falco sparverius) is the smallest and most common falcon in North America. Its diet consists primarily of insects and small mammals, with some birds. Some of the main prey items include:
- Grasshoppers, crickets, beetles, dragonflies – Kestrels are insect hunting specialists.
- Voles, mice, shrews, bats – Small mammals make up about 15% of their diet.
- Small birds like sparrows, starlings, flickers – Birds can compose up to 25% of their food.
- Occasionally frogs, snakes, small fish
Squirrels fall within the size range of prey a kestrel might eat, but they are not a preferred food source. Squirrels have thick fur and skin that makes them difficult to immobilize and kill quickly. They are also fast and agile in trees, making them a challenging target. Kestrels prefer easy-to-catch prey that can be eaten immediately like insects, lizards, and small rodents.
Hunting Squirrels
Although not their favorite, kestrels will opportunistically hunt squirrels when the chance arises. Here are some scenarios where a kestrel might go after a squirrel:
- Young squirrels just out of the nest are vulnerable targets. Kestrels can more easily kill juvenile squirrels.
- Squirrels frozen out in the open provide an opportunity. Kestrels use speed and surprise attacks.
- Injured, sick, or impaired squirrels are easier prey for kestrels.
- During winter when other foods are scarce, squirrels become a more worthwhile target.
- A coordinating pair of kestrels can have success hunting squirrels.
To attack a squirrel, the kestrel will dive abruptly and strike with its talons. It aims to puncture the skull and damage the brain or spinal cord for a quick kill. The squirrel’s thick fur and skin make this difficult. The squirrel may escape unless the kestrel can maintain its grip and repeatedly strike. Hunting squirrels takes considerable energy and carries risk of injury for the relatively small kestrel.
Squirrels as Prey
Squirrels are not a primary prey item for American Kestrels due to the following factors:
- Large adult squirrels are challenging prey for the small kestrels.
- Thick fur and skin makes it hard to immobilize squirrels quickly.
- Squirrels are nimble and quick in trees, able to outmaneuver kestrels.
- Plentiful alternative prey like mice and insects are easier to catch and kill.
- Hunting squirrels may risk injury and expend considerable energy.
Kestrels will eat squirrels when the opportunity arises, particularly younger ones, but overall squirrels make up a very minor portion of their diet. The kestrel’s small size limits them to eating smaller prey most of the time. They are better suited to catching insects, lizards, small rodents, and songbirds. Hunting adult squirrels is possible but quite difficult for kestrels.
Percentage of Diet
Studies on the American Kestrel diet have shown:
- Insects make up 35-60% of food by weight.
- Small mammals are 15-25%.
- Birds are up to 25%.
- Amphibians and reptiles are around 3%.
- Squirrels likely make up less than 1% of their diet.
This breakdown reflects how kestrels are highly adapted to catch insects and voles. Squirrels do not seem to represent a significant portion of their nutritional intake. Though capable of occasionally catching squirrels, the kestrels likely expend more energy hunting them than the reward gained.
Hunting Techniques
When hunting all types of prey including squirrels, American Kestrels utilize these specialized techniques:
- Perch hunting – Kestrels will perch and watch for prey movement below.
- Hovering – They can beat their wings fast to hover motionlessly before diving.
- Pounce attacks – Kestrels fold in their wings and dive suddenly to strike prey.
- Speed – They can dive at speeds over 100 mph to surprise prey.
- Stealth – Their pointed wings allow silent dives perfect for ambush attacks.
These attributes help kestrels overwhelm prey before it knows what happened. The speed and force of impact often stuns or kills instantly. When hunting agile squirrels, the kestrel has the advantage of surprise and maneuverability. If the initial strike fails, the squirrel usually escapes. Kestrels rarely engage in prolonged chases of squirrels in trees.
Do Kestrels Eat Flying Squirrels?
Flying squirrels are another potential prey animal for American Kestrels but are rarely taken. Reasons include:
- Flying squirrels only emerge at night, kestrels hunt by day.
- The loose skin and fur of flying squirrels allows them to survive falls from trees.
- Gliding gives flying squirrels an aerial evasion ability.
- They nest in tree cavities inaccessible to kestrels.
Flying squirrels are very challenging prey for kestrels to capture compared to their usual ground-dwelling rodent prey. The flying membranes and maneuverability in trees give flying squirrels an advantage over the falcons. There is minimal overlap between their activity periods and habitat use. Kestrels opportunistically eating flying squirrels would be extremely rare.
Conclusion
In summary, American Kestrels are capable of preying on squirrels but do not rely on them as a primary food source. Squirrels make up a very small portion of the kestrel diet compared to insects, small mammals, and birds. Hunting squirrels requires considerable energy expenditure and carries risk of injury for kestrels. They will opportunistically eat juvenile squirrels but have difficulty killing healthy agile adults. Kestrels are better adapted for catching insects in flight and ambushing small ground mammals. Squirrels are challenging prey that kestrels will only pursue when easier options are scarce.