1. Differential Behavioral Development in the Falconiformes to Fill Ecological Niches According
to Hunting Style
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Falconiformes
Family: Falconidae
Genus: Falco
Species: F. peregrinus,
F. sparverius,
F. columbarius,
F. mexicanus
There are twenty-nine recognized orders within the class Aves. Each of these orders
exhibit unique characteristics or behaviors that set them apart from the others. We will be
focusing our attention on the hunting behaviors that have developed within the order
Falconiformes with direct consideration of the North American birds included in the family
Falconidae. The species included in this family have similar morphologies but have developed
different hunting strategies which allow multiple species to share a range without directly
competing with one another for prey. Through the examination of the behavior of the Peregrine
Falcon, American Kestrel, Merlin, and Prairie Falcon we will discuss the differential
development that has occurred which allows these individuals to fill their different niches in the
environment as well as how these developments have allowed them to avoid conflict.
Peregrine Falcon
Male and female peregrine falcons look alike as far as color, but as with most falcons the
females are larger than the males. They range from about 15 to 20inches long and have a
wingspan of about 36 to 40 inches. They weigh about 600 to 1300 grams and have a hooked
beak (Regency Brighton). A mature peregrine falcon has a black cap and a mustache, long tail
with gray and white bands across it, gray on the back of the wings, and a pale throat and breast
with dark bars and spots (USGS).

2. Peregrine falcons have a world wide range. From Australia to North America the
peregrine falcon still prefers an open country. They can live anywhere from the tundra to the
high mountains. They have also been seen nesting in tall buildings, by the sea coast and in open
forests (Regency Brighton).
Peregrine falcons mate for life. They will sometimes come back to the same spot every
year to nest. The male and female will perform a courtship “dance” in the air. Both will rise
high in the air and take rapid dives down with each other. The clutch is usually 3-4 eggs. Both
the male and the female will incubate the eggs for about 28-32 days. Once the chicks hatch both
parents will feed and take care of the young. Once the young become mature they can live up to
20 years (New York State).
The Peregrine Falcon is well known for its high speed, some have even been clocked
flying as fast as 200 mph. The Peregrine Falcon’s speed is what makes them such good hunters,
allowing them to catch almost all of their prey in midair. They eat birds of many kinds and many
sizes with Pigeons being one of their favorite delicacies. When a Peregrine Falcon is flying and
sees is prey it will stay right above them. They will do what is called a “stoop” and dive down at
its peak speed and drive their sharp talons into their prey (Wisconsin Department of Natural
Resources). This impact kills the prey instantly with the pressure itself resulting in the death of
the prey. If the bird is light enough the Peregrine Falcon will swoop down again after hitting the
prey and carry it off to eat, if the prey was too heavy to carry the Peregrine Falcon will let it drop
to the ground and it eat there (Regency Brighton).
American Kestrel
Out of all the falcons in North America the American Kestrel is the smallest. Females
average 25 cm in length, 120 g in weight with a wing span of 57 cm. The males are just below
that averaging 24 cm in length, 111g in weight with a wing span of 55 cm (Wikimedia). There is

3. yet another difference between male and female Kestrels, their coloration. Their difference in
coloration is a very successful way to identify Kestrels in the field. The female Kestrels have a
lighter, tan breast with brown streaks. The back of the wings are rust in color along with their
tail and nape. The back of the females also looks as if there are stripes on them. The males have
a blue-gray color to the back of their wings and they have what looks like spots instead of stripes
like the females. They also have a pale belly. Both male and female have hooked beak, long
pointed wings, a gray crown with white cheek and mustache markings in black (Texas Park and
Wildlife).
The American Kestrels habitat is wide spread. Kestrels mainly need open space to find
prey and hunting and they also need many perches and cavities for nesting. Their needs are quite
simple therefore the American Kestrels are found in many places such as; grasslands, plains,
marshes, suburbs, deserts and freeways (Wikimedia).
Male and female Kestrels form a tightly bonded breeding pair. Courtship starts after the
male claims his territory. He may flutter for his female or even bring her food to intrigue her
(Wikimedia). Kestrels are cavity nester. They use places such as holes in trees, nest boxes,
buildings and cliffs. There are on average three to six eggs laid. It takes about 30 days to hatch.
After the young are born both the male and female take care of them (Greybird Publishing).
Once the young are grown there average life span is ten years (Wikimedia).
Kestrels hunt small animals such as bats, insects and mice. The unique hunting strategy
that Kestrels use is hovering (Texas Park and Wildlife). This is what makes them distinct within
the Falconidae. They are not well known for chasing their prey, instead they are known for
hovering over them and pinning their prey to the ground so they can’t move. They also can use a
perch that is close enough to their prey where they can get right above them to pin them against

4. the ground. The American Kestrels also is known for flying in a figure eight formation and
sometimes circles before attacking. Just before a Kestrel attacks its prey it bobs its head and
pumps its tail. American Kestrels also have been seen capturing prey in flight and nest robbing
(Wikimedia).
Merlin
The Merlin, Falco Columbarius, is a small falcon with a range covering much of Canada
and the Western United States. It has been called the “Pigeon Hawk” in the past because the
flight of this falcon is sometimes mistaken for that of a member of the Columbiformes. The dark
tail has two to five contrasting bands that aid in distinguishing the Merlin from the Peregrine and
Prairie Falcons (Clark and Wheeler 1987). This falcon feeds predominantly on small birds which
are captured in short, fast flights. For this reason, this species tends to prefer habitats with semi-
open areas. These habitats provide nesting sites as well as open areas that improve or simplify
hunting. Their dominant prey species, the House Sparrow, is also common in these regions.
In general, Merlins attack small to medium sized birds that are less then 50 g. Their
attacks are sometimes on perching individuals but the majority of the prey is captured mid-flight.
The Merlin perches in a location where it can scan a large area for prey. It is from these perches
that a hunt begins (Sodhi et al. 1991). They normally fly rapidly below treetops or close to the
ground. It is unusual for them to dive toward prey at high speeds and from great heights (Fox
1964). Prey is generally killed by a bite to the neck instead of the force of the impact or the claws
as with the Prairie and Peregrine Falcons (Sodhi 1992). On occasion the prey will attempt to out
fly the attacking falcon which results in ringing flights. These aerial chases result in the prey and
predator increasing their altitude as they fly in circles. Cooperative hunting between two Merlins
is rare.

5. The hunting behavior is most commonly observed in the early morning and late
afternoon. During the nestling season individuals with larger broods spend more time hunting
then those with fewer young while those males with a high amount of prey in their territory
spend less time hunting.
While the Merlins mainly feed on other, smaller, birds they also prey upon a small
number of mammals, insects and reptiles. Their most common prey is characterized as a species
that is abundant in the Merlins range and forages away from cover which makes it vulnerable to
attack. The small birds that are attacked include larks, pipits, sparrows, and small waders (James
et al. 1993).
Prairie Falcon
The Prairie Falcon is a large, pale brown falcon with distinctive black malar streaks, a
dark ear-patch, and a white patch between their eye and the ear. When these falcons are in flight
they can be identified by dark axillaries. The trailing edge of the underwing-coverts is also dark
and contrasts the light color of the underwing (Clark and Wheeler, 1995). They are found in
western North America and prefer territory with cliffs and bluffs surrounded by open plains and
shrub-steppe deserts. The seasonal movements are a result of changes in food availability. Once
a pair has chosen an area to nest they will return to it each year and raise a brood of
approximately four young (Anderson et al., 1997).
The Prairie Falcon is equipped for high speed chases and rapid dives. They will typically
hunt by flying rapidly 10-60 meters above the ground in order to locate prey before gliding
directly to the target. This behavior changes depending on the season and weather conditions.
When it is sunny or windy the falcons will soar as high as 100 meters. Once they spot prey they
will tuck their wings in and dive at a 30-60o angle, level off near the ground and glide the last 10-
300 meters to their prey without flapping their wings. “Oblique decent from flapping flight” is a

6. second attack type. In this case the falcon flies at low altitudes and descends rapidly in a shallow
dive that rapidly increases its speed as it approaches the prey. “Opportunistic low flight”
involves flying low along the ground and attempting to catch anything flushed out of the cover
by their appearance overhead. These birds are also seen “still hunting” frequently. They will
perch on utility poles or other vantage points and scan an area for prey. They will then dive close
to the ground and fly rapidly toward the prey, gliding the last few meters (Phipps 1979).
On top of these individual hunting strategies, the Prairie Falcon will hunt with Harriers
on occasion. In these cases, the Prairie Falcon will fly 30-50 meters above and 50-100 meters
behind the Harrier as they fly over open fields. The falcon will then attack the birds flushed by
the Harrier (Anderson and Squires).
In addition to these, the Prairie Falcons will imitate the flight patterns of other birds to
deceive prey and steal prey from other raptors. This allows the falcons to be closer to the prey
before they become alarmed (Anderson and Squires). On occasion the falcons will observe
another raptor hunting and stoop at or attack this bird as it returns with the prey or sits on a
ledge. This will sometimes cause the other raptor to drop the prey as it attempts to avoid the
falcon. The prey is then retrieved by the falcon and returned quickly to the nest (Holthuijzen et
al. 1987).
These falcons also pursue a variety of prey. They hunt primarily in the early morning and
late afternoon while remaining in shaded areas or nesting sites during the midday. The species
that are used for prey vary depending on the region but they are generally small mammals or
birds and occasionally small reptiles. Some of the birds taken in clued the Horned Lark, Western
Meadowlark, Mourning Doves, and Brown-capped Rosy Finches (Beauvais et al. 1992). The

7. abundance of the prey species also determines how extensively they are used by the falcon
(Anderson and Squires).
These four species are members of the family Falconidae. While their morphology is
similar as well as some of their overall behavior the hunting behavior of each of these species is
unique when compared to the others. The Peregrine Falcon is a large bird for this family that
primarily hunts at high speed. Individuals of this species are known for their ability to kill prey
on impact in mid-flight through high speed dives and the use of their talons. The Prairie Falcon is
also capable of high speed attacks but they do not kill the prey on impact and in many cases the
prey is ambushed on the ground. This species is capable of multiple hunting patterns and often
mimics other birds or hunts with them. This behavior makes them highly opportunistic predators
that will make use of whatever they can and hunt in any way necessary.
Contrary to these high speed hunters, the Merlin and the American Kestrel practice an
ambush style of hunting. The American Kestrel is highly regarded for its ability to hover which
allows it to wait above its prey and pin it to the ground. This is a entirely different method from
the fast paced strikes shown by the Peregrine and Prairie Falcons. The Merlin will take prey mid-
flight, similar to the larger birds, but they do not dive at high speeds or from a great height. They
also kill their prey with a bite to the neck instead of with their talons or the force of the impact.
While each of these species pursue and capture prey in different ways they have a similar
morphology. The differences that are observed in hunting behavior are a result of the types of
prey available to each species as well as the ways in which the bird uses its body structure. The
behavioral modifications that have occurred between these species allow them to fill various
niches in an environment and avoid direct competition with one another for prey.

8. References
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