The American Kestrel (Falco sparverius) is a small falcon native to the Americas. It is the smallest and most common falcon in North America. The American Kestrel is able to fly at remarkably fast speeds, especially considering its small size. In this article, we will examine the flight capabilities of the American Kestrel and try to answer the question: How fast can the American Kestrel fly?
Average Flight Speed
The American Kestrel has an average horizontal flight speed of about 31 mph (50 km/h). However, this can vary considerably depending on the wind conditions and whether the kestrel is flying with or against the wind. Headwinds or tailwinds can significantly impact its airspeed.
During level flight in calm conditions, the average speed is about 31 mph. With a significant tailwind, the American Kestrel has been recorded flying at speeds over 65 mph. When flying into a headwind, its ground speed can be reduced to 15 mph or less. So the airspeed ranges from about 15 mph to 65 mph, with an average cruising speed around 31 mph.
Maximum Speed
The highest reliably recorded speed for the American Kestrel is 69 mph (111 km/h). This was its measured stoop or dive speed achieved while hunting prey. There are anecdotal reports of American Kestrels stooping at speeds up to 75 mph, but these have not been scientifically documented.
During the stoop, the kestrel goes into a steep dive, partially closing its wings to minimize drag. This allows it to accelerate rapidly downwards under the force of gravity. The extra speed helps the kestrel strike and capture prey with greater force. Through this diving technique, the American Kestrel can reach speeds about twice as fast as its normal horizontal flight.
Factors Affecting Speed
Several factors influence the flight speed of the American Kestrel:
Wind
As mentioned earlier, wind conditions have a major impact on the kestrel’s ground speed. With a strong tailwind, it can ground speeds over 60 mph. Facing into a headwind, its ground speed could be less than 20 mph while its airspeed remains at 30 mph. Kestrels take advantage of tailwinds when available to conserve energy.
Prey Detection
When hunting, the American Kestrel will fly more slowly while scanning the ground for prey. Once it spots its target and initiates the attack stoop, its speed will rapidly increase to up to 69 mph. So its velocity depends greatly on whether it is actively chasing prey.
Altitude
The higher the altitude, the faster a kestrel generally flies. It can gain more speed diving down from greater heights. Kestrels may also fly faster at higher elevations where the air is thinner to increase lift.
Angle of Descent
During the stoop, the kestrel’s speed is dependent on its angle of descent. The steeper the diving attack, the faster it can accelerate under gravity’s pull. Shallower attack angles result in slower stoop speeds.
Weather Conditions
Rain, high winds and other extreme weather can slow a kestrel’s flight speed. Strong headwinds require more work and energy to fly against. Gusty or turbulent winds also make flying more difficult. Poor visibility in rain or fog may also reduce speeds.
Geography
Kestrels are slightly larger and faster in the northern parts of their range. Larger variants in Canada can reach higher stoop speeds than the smaller subspecies in Central America and the Caribbean. The largest kestrels are found in areas like Alaska where the added speed helps them survive in harsh conditions.
Speed Relative to Other Birds
The average horizontal flight speed of 31 mph makes the American Kestrel faster than many common birds, but slower than some other raptors. In comparison:
Slower Birds
– Pigeons fly around 20-30 mph
– Mallard ducks fly around 30-40 mph
– Sparrows fly around 20 mph
– Robins fly around 25 mph
Faster Birds
– Peregrine Falcons can reach 200 mph in a stoop
– Golden Eagles can reach 150 mph in a stoop
– Red-Tailed Hawks fly around 35-45 mph
So while far short of the Peregrine Falcon’s record stoop speed, the American Kestrel is still one of the faster small birds. Its ability to accelerate to 60+ mph gives it an advantage when pursuing prey. The kestrel fills an ecological niche for a small, fast raptor.
Flight Speed and Hunting
The American Kestrel’s speed is a key adaptation for its hunting strategy. Here’s how its flight capabilities are used when catching prey:
– It flies at moderate speeds of 20-30 mph while searching for prey from an elevated perch.
– Once prey is spotted, the kestrel dives steeply at its target accelerating to 55-60 mph.
– Near the ground, it pulls up, extends its legs and grabs the prey in its talons.
– The extra momentum from the high-speed stoop helps it capture and carry off larger prey like small rodents.
Its ability to quickly switch from efficient cruising to rapid diving speeds gives the American Kestrel an effective technique for catching prey. The high stoop speed compensates for its small body size, allowing it to take down larger prey.
Prey Item | Average Prey Size | Kestrel Stoop Speed Needed |
---|---|---|
Large Insects | 2-3 inches | 25-35 mph |
Small Birds | 5-7 inches | 45-55 mph |
Voles | 3-6 inches | 50-60 mph |
As this table shows, the kestrel must reach higher speeds to successfully capture larger prey items like voles and small birds. This ability gives it access to a wider range of food sources.
Kestrel Flight Abilities
In addition to speed, the American Kestrel has several other flight adaptations that aid its hunting:
– Rapid Acceleration – It can go from 0 to 30 mph almost instantly, enabling quick takeoffs when prey appears.
– Tight Turning Radius – Its short, rounded wings allow very tight turns and rapid course changes in flight.
– Swift Dive Initiator – Special feathers above the eye slash airflow, enabling the kestrel to swiftly start its stoop.
– Aerial Hovering – Unique wing motion lets it hover in place while scanning for prey below.
– Head Stability – Special feathers keep its vision steady as it zooms through turbulent, high-speed dives.
These capabilities all combine to make the American Kestrel an agile, speedy hunter able to exploit small openings to catch prey.
Conclusion
The American Kestrel is built for speed and rapid aerial maneuvers. While its average horizontal flight speed is around 30 mph, it can reach stoop speeds over 60 mph in a hunting dive. This allows it to catch a wide range of prey from insects to small rodents. The kestrel’s flight abilities including tight turns, swift acceleration, hovering and head stability enable it to capitalize on brief opportunities when pursuing prey. So the next time you see an American Kestrel, watch closely and you may witness the speedy flight capabilities that give this falcon an edge as a predator.