Kestrels are small falcons that are found worldwide. There are about 17 different species of kestrel, with some of the most common being the European kestrel, the lesser kestrel, and the American kestrel. Kestrels hunt by hovering in place high above open country and swooping down on prey. They mainly eat small mammals, insects, and reptiles, but some larger kestrel species are capable of killing small birds as well.
Kestrels have excellent eyesight which helps them spot and capture prey while flying. Their wings allow them to hover in place and also to swiftly change direction when pursuing prey. Kestrels use their sharply hooked beaks and talons to kill and carry prey after capture.
So do kestrels eat other birds? The answer is that while kestrels mainly feed on mammals, insects, and reptiles, some of the larger kestrel species are definitely capable of preying on small birds occasionally. However, birds do not make up a major portion of any kestrel species’ diet.
Feeding Habits of Kestrels
The most widely distributed and also smallest kestrel species is the common kestrel. This species weighs around 120-140g and is about 28-35cm in length. Given its small size, the common kestrel feeds mostly on small mammals like voles, shrews, and mice as well as insects and lizards. This species does not normally hunt other birds.
Larger kestrel species are able to take down small bird prey though. The American kestrel has been observed feeding on small birds like sparrows, warblers, and thrushes on occasion. The greater kestrel which is native to Africa and southern Asia is also large enough to prey on small birds at times.
The largest kestrel species is the grey-headed kestrel which can weigh over 300g. This African species could potentially prey on larger bird species, but is still believed to get most of its nutrition from rodents and insects.
So while not all kestrels eat other birds, the larger species are certainly capable of doing so, especially given their excellent hunting abilities. However birds do not make up a major part of the diet for any kestrel species compared to mammals, insects, lizards, and amphibians.
Bird Hunting Techniques
Kestrels that do feed on birds use a variety of hunting techniques and adaptations to capture their prey. Here are some of the main ways kestrels can attack and feed on birds:
– Dive Bombing – Kestrels will hover in place above open fields then go into a steep dive towards a potential target. They can reach speeds over 40 mph in these hunting dives.
– Aerial Pursuit – If the initial dive startles but misses the bird, the kestrel can chase after it in flight and run it down with its speed and agility.
– Ambush – Kestrels sometimes perch and wait to ambush unaware birds that come near. They drop down quickly to surprise their prey.
– Talon Attack – Large talons and sharp claws allow kestrels to swiftly kill and carry bird prey after capture.
– Keen Vision – Excellent eyesight allows kestrels to spot and focus in on potential bird targets, especially when hovering at high altitude.
So kestrels are well equipped to hunt bird prey. However, most species still tend to prefer the ease of capturing small rodents and insects that can’t escape their diving attacks quite as easily as birds can. But larger kestrels do have the capabilities to actively hunt and feed on some bird species.
Bird Prey of Different Kestrel Species
The frequency with which different kestrel species feed on birds depends on their size and also habitat. Here’s a breakdown for some of the main kestrel types:
American Kestrel
The American kestrel is widespread across North America and can be found in various habitats from open fields to deserts to cities. This is one of the more common kestrel species observed feeding on birds, which may include:
– Sparrows
– Warblers
– Thrushes
– Hummingbirds
– Jays
– Chickadees
However, this kestrel still prefers easy small mammal prey and only occasionally eats other birds.
Lesser Kestrel
This small species is distributed across Africa, Europe, and Asia in open country and steppe regions. The lesser kestrel does not typically hunt other birds and sticks to insects, lizards, rodents, and bats.
Eurasian Kestrel
Also known as the European kestrel or common kestrel, this is the most widespread kestrel species. It feeds mainly on small voles and mice across Europe, Asia, and parts of Africa. There is little evidence they actively hunt bird prey.
Grey-headed Kestrel
As the largest kestrel species, the African grey-headed kestrel is potentially capable of feeding on some mid-sized bird prey. But in practice it sticks mainly to rodents, lizards, and insects across its savannah and grassland habitats.
So in summary, while many kestrel species could potentially eat other birds, most stick to small land-based prey like mice and lizards. Only the larger American kestrel seems to regularly include a reasonable amount of bird prey in its diet. And even in this case, birds do not make up a majority of its nutrition.
Suitable Bird Prey
Given their hunting skills and adaptations, there are certain types of birds that kestrels are better equipped to prey upon. Here are features that make some bird species more vulnerable to predation:
– Small size – Kestrels can only realistically carry bird prey less than about 50-60g in weight. Larger birds like pigeons are too big.
– Ground dwelling – Birds that spend time on the ground like sparrows can be more easily ambushed from above.
– Open country – Birds in open fields lack cover from diving kestrel attacks.
– Abundant – Plentiful species in an area provide more hunting opportunities.
– Slow flying – Poor flyers have less ability to evade strikes.
– Younger – Juvenile and fledgling birds are more vulnerable.
– Distracted – Birds focused on other activities like feeding are easier surprise targets.
Here are some examples of bird prey that fit these criteria:
Prey | Average Weight | Habitat |
Sparrows | 24-40g | Fields, backyards |
Warblers | 8-25g | Woodlands, shrubland |
Thrushes | 23-47g | Woodland edges |
So open country birds in the 20-50g range that spend time on the ground and fly somewhat slowly are suitable prey options for kestrels if they want to feed on birds occasionally.
Hunting and Feeding Behavior
Kestrels exhibit specific hunting behaviors when targeting bird prey:
– Perch hunting – Kestrels will sit and wait on an elevated high perch scanning for potential prey activity below.
– Hovering – Hovering in place above open fields allows kestrels to spot prey while remaining nearly motionless.
– Dive bombing – Once spotted, kestrels may enter into a sharp dive towards the prey from their perch or hovering position.
– Aerial pursuit – If the initial strike misses, the kestrel will chase the fleeing bird target.
– Talon strike – Sharp talons are used to snatch and kill the bird prey in flight or just after landing.
– Plucking – Kestrels pluck bird prey before feeding by removing all the flight feathers.
– Tearing – The kestrel then tears the bird apart and consumes small shredded pieces.
– Consumption – The bird prey is completely consumed except for indigestible matter like feathers, bones, and claws.
So kestrels have very effective and precise bird hunting strategies. But again, they still focus mainly on easy rodent prey and only occasionally go after birds to supplement their nutritional needs.
Impact on Bird Populations
Given that birds only make up a very small portion of their diet, kestrels do not have a major impact on songbird populations overall. However, in localized areas they may put pressure on certain vulnerable species, especially in decline.
Here are some examples of possible local impacts:
– American kestrels may occasionally prey on significant numbers of small sparrows in areas where sparrow populations are declining.
– Eurasian kestrels could potentially contribute to reduced warbler breeding success in certain habitats where they are abundant.
– Lesser kestrels may hamper endangered grassland bird species that nest on the ground in their European habitats.
But these localized impacts are minor compared to much more significant threats like habitat loss, building collisions, outdoor cats, and climate change.
On the whole, the predation rates of kestrels do not appear to be causing declines or having major detrimental effects on abundance of small bird populations on a wider regional or continental scale. Their influence is likely minimal outside of some isolated scenarios involving localized endangered species.
Defense Against Kestrels
Birds have evolved certain defenses to help protect themselves against predation from kestrels and other raptors. Some anti-predator adaptations include:
– Mobbing – Flocking together, dive bombing, and scolding can help startle and intimidate kestrels.
– Alarm calls – Loud alarm calls alert other birds in the area to the potential threat.
– Hiding – Ducking into dense shrubs or brush provides cover from air attacks.
– Crouching – Holding perfectly still minimizes motion to avoid detection.
– Camouflage – Plumage coloring helps some species blend into their surroundings.
– Nest defense – Diving and attacking predators near the nest may drive them off.
– Injury feigning – Some species pretend to be injured to distract kestrels from nests or young.
– Predator identification – Recognition of kestrels allows for early evasion and defense.
These adaptations allow many bird species to detect kestrels early and minimize the chances of being ambushed or caught off guard. So most small birds are primed and ready to react to the predation threat posed by kestrels in their environment.
Coexistence of Birds and Kestrels
Despite occasionally preying on other birds, kestrels tend to coexist relatively well alongside small bird populations for a few key reasons:
– They prefer to feed on mammals and insects which makes up the large majority of their diet. Hunting birds requires more energy.
– Most kestrels only weigh 100-200g so they can only capture smaller bird prey, limiting their impact.
– Defense adaptations like mobbing and alarm calls minimize the predation risk for many bird species.
– Abundant bird prey provides plenty of options so no one species feels excessive pressure.
– Kestrel populations are generally stable or declining rather than increasing and expanding.
– Habitat loss impacts both kestrels and songbirds so both suffer declines.
So while some predation occurs, kestrels are not dependent on other birds as a primary food source. This combined with the abundance of many small bird species allows coexistence with minimal detrimental impacts on overall bird population stability in most ecosystems.
Conclusion
Only some of the larger kestrel species actually prey with any regularity on other birds. Most kestrels by far prefer small mammals like mice and voles as their primary food. But American kestrels, Eurasian kestrels, and other large species do occasionally feed on small birds like sparrows, warblers, and thrushes. These kestrels use hunting techniques like hovering, dive bombing, and aerial pursuit to strike prey on the wing or on the ground. While kestrels can impact local rare bird populations in isolated cases, their low dependence on birds as a food source means they generally coexist well alongside other small bird species. On the whole, habitat loss remains the major threat to both kestrels and songbirds rather than excessive predation pressure. So in most ecosystems, birds only make up a very minor supplemental part of the kestrel diet.