About Peregrine Falcons
Peregrine Falcon Behavior by Janet Linthicum
should find an observation site with optimal visibility, but where
their presence does not interfere with normal Falcon behavior. At
Morro Rock we are fortunate in that we can watch Peregrines
throughout the year from the convenience of a parking lot.
In some cases
distant locations can provide a better overall view of a cliff and
of Falcons coming and going. However, those with little observation
experience with Peregrines may find them difficult to spot, and
vocalizations can be very helpful.
are disturbed enough that observers should retreat and find another
location immediately. The Falcons respond more to an observer above
the nest than to one below or across from it. Signs of lower-level
disturbance can include soaring above the cliff silently (watching
the observer), perching where they can watch the observer rather
than engaging in normal behavior, and sometimes displacement
aggression such as assaulting a cormorant, gull, or other large bird
in the cliff vicinity.
a Falcon seems to be watching the observer(s), they should consider
retreating to a more distant location. Even if the birds are not
disturbed, they may be less inclined to engage in the behavior the
observer is there to see if they are distracted. Before beginning
observations, find a spot from which to observe for extended periods
without becoming uncomfortable, distracted, or eager to depart.
observers should learn to distinguish the male from the female,
preferably while both are still visible simultaneously. The best
indication of sex is size, females being larger than males. However,
it can be extremely difficult to sex a single bird on this basis,
and experienced observers often err.
If there are
identifying aspects of individual Falcons, they can be very helpful
once incubation has begun and the observer rarely sees both birds at
once. In many pairs, the female looks darker overall on the breast
and farther up toward the neck, and may have a darker, slightly
brownish tinge to the back. The male looks more white on the breast
from a distance, and silver on the back and especially in the rump
area in flight. Some males are vividly orange around the cere
(fleshy portion of beak) and feet (as opposed to bright yellow or
yellowish-orange). There is much variation among individuals, so get
to know the pair if possible.
one of the pair is a yearling. Yearlings have bleached considerably
during the year and may appear "blond" rather than brown, and could
be confused with an adult at a distance. A good method of checking
is to note whether the marks on the breast are vertical streaks or
horizontal bars. Occasionally, one may encounter a yearling that has
already molted partially by its first spring, or a two-year-old that
molted incompletely its first year. These birds may breed
successfully, although many do not.
are higher-pitched, and in flight their wings are more narrow with
"sharper" ends. Peregrines
molt their flight feathers during the
breeding season, with females usually beginning to molt before
males. Differences in the gaps in wings and tail can be helpful in
distinguishing individuals during a given day's observation.
(Do we have
access to any sound files of various vocalizations?)
repetitious, staccato ee-chup ee-chup ee-chup sound. Males have a
higher-pitched "eechip". Variations include a slower chip chip
chip, usually during ledge displays and while feeding young.
Ee-chup usually implies social recognition, but a very similar
sound, louder and more staccato, is given as a response to vagrant
raptors, usually Peregrines.
CACKING. Very loud cack cack cack -- A response to disturbance,
either a raptor or other animal (including the observer) too near
WAILING. A long, slow, ascending waaaaaa waaaaaa waaaaa. Sometimes
connotes hunger, but also used in a variety of circumstances.
Youngsters have a more insistent variation of this call, which is
often referred to as hunger screaming.
CHITTERING. Like ee-chupping but quicker and less defined. Usually
used by birds in proximity, often when one bird is being made
uncomfortable by some aspect of the interaction, or during play by
sometimes store uneaten food for later retrieval. They
usually have several favorite cache spots on the cliff or
elsewhere in the territory.
CASTING The Falcon hangs its head and wags it from side to
side with mouth open. Eventually a pellet (casting) of
non-digestible material is expelled.
BOWING A general
display used in many situations, especially as part of courtship.
MALE OR FEMALE LEDGE DISPLAY The Falcon stands over the
nest depression (scrape), leaning forward (bowing) and
ee-chupping. The male often stares at the female during a male
ledge display. Sometimes the Falcons concentrate courtship in one
spot, then suddenly lay eggs in a different, often more cryptic
location. If both birds are suddenly no longer seen together, or
activity at the expected nest subsides, suspect that the birds
have moved and that they might have eggs.
SCRAPING Ledge displays are often accompanied by scraping.
Either bird can do this. The Falcon runs its breast through the
substrate or nest depression, pushing out with its legs behind.
The bird is forming the nest cup (scrape), but this is also part
of courtship. Scrapes may be made at several potential ledges
before one is finally chosen for laying.
MUTUAL LEDGE DISPLAY Often this is precipitated by a male
or female ledge display. The other bird joins the first on the
ledge and both bow and ee-chup over the scrape, sometimes touching
bills. This can also happen outside the aerie
PRE-LAYING Both birds are visible for extended periods
outside the nest. This can happen when there is a partial clutch.
PAIR FLYING Both birds engage in high speed acrobatic
displays, with no apparent hunting or territoriality involved.
This indicates that the female is probably not lethargic with eggs
yet. Sometimes males engage in spectacular flight displays while
the female watches.
Self-explanatory. The female is probably not laying eggs yet.
FOOD TRANSFER The male offers food to the female by
approaching her or standing near, with food in talons or beak,
ee-chupping. The female takes the food from the male, usually
ee-chupping or wailing. This can happen in the air or perched. The
male often signals the female that he has food by wailing as he
approaches the cliff. These occur, male to female, in the air or
at a perch throughout the nesting season. As incubation
approaches, concentrate on the male after the transfer. He is
often the key to incubation as described later.
LANDING DISPLAY AND HITCH-WING POSTURE (male) A
pre-copulatory display in which "shoulders" are held high, as if
in a shrug, and male often prances as if on tip-toe.
COPULATION The female leans forward and moves her tail to
one side. The male rests on his tarsi on her back, flapping his
wings, and presses his tail underneath the female's. Copulations
are usually accompanied by wailing on the female's part, and
chittering or ee-chupping by the male. When the male departs, the
female usually ee-chups a few times, and often rouses (shakes her
feathers). Before and during egg laying, Peregrines
frequently. When the clutch is complete they rarely copulate.
before and during the period of egg laying (approximately eight
days for four eggs) the female becomes lethargic. She can look
"dumpy", including fluffed-up feathers while perched, hanging her
vent feathers (the feathers in front of the cloaca, underneath the
tail) to an unusual degree, leaning slightly forward while
perched, waddling when walking, dozing with one or both eyes
closed for long periods, and generally remaining near the nest and
being inactive. She might also spend considerable amounts of time
in the nest by herself. After laying an egg, she may have periods
of being more active, but lethargy is a general demeanor to note.
Those without much previous experience with Peregrines
aware it is comparative and subjective.
PARTIAL CLUTCH The Falcons usually begin incubating after
the second or third egg, even if a fourth is to be laid. Before
incubation starts, they often "guard" the eggs, standing in the
nest or within sight of the eggs. This is an indication that at
least something is in there. Again, the male is the key. After a
food transfer or nest exchange, watch the male. If he enters the
nest for a while (even a long while) then comes out and perches
out of the nest while the female also remains outside, you are
fairly safe in assuming that full incubation has not started.
INCUBATION During the normal course of incubation, one of
the adults is nearly always on the nest. Exceptions are during
disturbance, for short periods on particularly warm days, or for a
few minutes during food exchanges. The female does the majority of
incubation. The male brings food to her several times daily, or
sometimes simply relieves her and takes a turn on the eggs while
the female eats, preens, and relaxes. When she returns to the nest
to relieve the male, he usually appears on the ledge when she
disappears; an unaware observer may think only one bird was
involved in a brief visit to the ledge. A common mistake is
failure to realize that the bird leaving a spot is not the same
bird that just arrived there (i.e., nest exchange as opposed to
just perching briefly). This is why it is important to be able to
distinguish sexes. During food exchanges the male arrives with
food, often wailing or ee-chupping and passing in front of the
where the female can see him. She then exits the aerie
takes the food, either at a perch or in the air. This exchange
gives a good opportunity for locating the nest. The best way to
determine that incubation is occurring is to train your attention
intently on the aerie
and be certain that the attending Falcon
remains in the nest until relieve by the other adult. This can be
very tedious, but is worth the trouble because otherwise it is
possible to see a lot of behavior, and yet not determine what is
happening. Observation of several sequences in which an adult attends until a nest exchange occurs indicates that incubation is
If the observer is unable to see the aerie
behaviors may be helpful. For example, voluminous excretion has
been used to determine incubation in coastal California, where the
observer sometimes cannot see the cliff face that the aerie
When a nest exchange is occurring (e.g., the male brings in food
and disappears toward the nest, and soon thereafter the female
appears coming from that area) watch the female. After she
perches, she soon slowly leans forward and emits a large quantity
of excreta. This can also occur while flying. This behavior
indicates that the Falcon has been unable to defecate for a
prolonged time (i.e., has been incubating). Also watch for rousing
(shaking of all feathers in a relaxing manner), stretching, and
preening intensively. All of these are normal behaviors, but tend
to be exaggerated after a stint of incubation.
Egg Failure Some pairs lose their eggs to breakage,
weather, or other factors. If this occurs while laying is still
underway, they may relocate to a different ledge and attempt to
complete the clutch there. If the clutch has been completed and
incubation is underway, and the eggs are then lost, the first egg
of the second clutch is usually laid approximately fourteen days
later if recycling occurs. Sometimes, Falcons exhibit the "lost
look" after failure, returning to the scrape repeatedly but not
staying, and wailing frequently. The Falcons usually change ledges
after failure, sometimes quite a distance away (possibly an
alternate cliff), so do not assume they have "given up" if they
are not in the usual places. Re-nesting may occasionally occur
after loss of a young brood, or even after a second set of eggs is
Clues to failure include
either adult eating full meals without delivering food to the
, decreased territoriality and presence at the cliff or
resumed courtship behavior if recycling is occurring, and frequent
approaches, the adults often become more aggressive. During the
early nestling stages the young require almost constant brooding,
which can be hard to distinguish from incubation. The main
difference is that after a food exchange, the female takes the
prey into the nest rather than eating outside (she may pluck it
before entering the aerie
During the early nestling stage most females do the majority of
feeding. Males provide food, and may brood young during the
female's absence. After approximately two weeks, depending on
ambient temperature and number of chicks, the young no longer need
constant brooding. Therefore, both adults are often outside the
nest for extended periods. This is easily mistaken for nest
Depending on size of prey and number of young, the nest may only
be visited a few times a day by the adults. Clues to presence of
young include continued territoriality by adults, absence of
courtship behavior, frequent hunting attempts, sometimes hunger
screams of young, and, of course, prey deliveries.
As the young age, they begin eating on their own, and sometimes a
prey delivery is extremely brief. Also, late in the nestling stage
the female hunts, and the male as well as the female feeds young.
Some males are absent from the immediate nest area most of the
day, either hunting or perched out of sight, except when
Out of the Nest
Recently fledged young
are brown with vertical streaks on the front, and may appear
somewhat larger than adults of the same sex, because their flight
feathers are slightly longer. Their wing tips in flight are more
rounded than those of adults. They often flap their wings while
perched (exercise), land clumsily, and engage in mock combat,
tumbling and playing together in the air.
When an adult is in view, they "hunger-scream", and often chase
the adults. In begging while flying, they sometimes appear to flap
their wings quickly (flutter). Seen from above, powder down may
cause young in flight to appear bluish, leading to confusion with
adults; however young of the year have conspicuous light tips on
the tail feathers.
alpha-numeric bands in addition to U. S. Fish and Wildlife Service
(USFWS) bands. These bands usually have two characters, numbers or
letters or both, that are meant to be read at a distance. When one
of these bands is read, it is necessary to draw the band as it
appears on the leg for reporting purposes. This is because there
are several combinations of the same characters in existence, and
how the characters are arranged on the band is important for
identifying it. For example, characters can be horizontal and/or
vertical, and may have a line between them. Some bands are more
than one color.
Go to Page 2 / About Peregrines
A brief summary of laws protecting Peregrine Falcons