The peregrine falcon (Falco peregrinus) is a widespread bird of prey that is found on every continent except Antarctica. These falcons are best known for their incredible diving speeds, reaching over 200 mph when stooping down on prey. Their high-pitched cries are a distinctive part of their behavior and serve several important functions for the birds. In this article, we will explore why peregrine falcons vocalize and what their different calls mean.
Alarm Calls
One of the most common reasons peregrine falcons cry out is to signal alarm or alert others to danger. Their loud, repetitive calls act as warning bells, telling other falcons or even different species of birds that a predator or threat is near. This benefits the individuals sounding the alarm by potentially scaring away the danger, and it also alerts others nearby to be on guard. Some key examples of alarm calls include:
- Sentinel call – A series of loud “kak-kak-kak” cries given by adult peregrines when surveying the landscape from a high perch. These sentinel calls help warn others of impending danger.
- Disturbance call – Harsh, grunting “kaa-kaa-kaa” or “ark-ark-ark” notes triggered by human disturbance or interference.
- Alert call – Sharp “kak” or “kek” calls used to signify immediate danger or the presence of a predator.
By vocalizing when alarmed, peregrines can coordinate their escape or defense as well as alert their young to hide or take cover. The alarm calls provide key information that helps the falcons survive in their environment.
Territorial Calls
Another major reason for vocalizations in peregrine falcons is declaring ownership of territory and warning away intruders. Their conspicuous calls serve to broadcast the presence of a mated pair or territorial falcon so that others avoid the area. Some typical territorial vocalizations include:
- Bonding call – Extended loud screams given by mated pairs, often as a duet. These help strengthen the pair bond while also marking the territory.
- Resident call – Loud, sharp cries by adult peregrines throughout the breeding season. Communicates residency and serves as a stay away signal.
- Warning call – Harsh “kak-kak-kak” sounds made during conflicts with intruders. Indicates aggression and signals the intruder to retreat.
By using easily localized vocalizations, peregrines can avoid dangerous physical confrontations while still being able to protect their territory from conspecifics during breeding. The warning calls give intruders a chance to flee before an attack.
Begging Calls of Nestlings
In addition to adult vocalizations, young peregrine falcons at the nest produce loud, repetitive begging calls to solicit food from the parents. These vocalizations consist of short, sharp cries repeated over and over. As the nestlings get older and their energy demands increase, the begging calls get louder and more insistent, reaching their peak volume around 2-3 weeks after hatching.
The begging calls stimulate the adult falcons to deliver food to the nest. Both the male and female peregrine participate in hunting and provisioning the chicks. When they return to the nest with prey, the hungry youngsters immediately start their incessant vocalizations to draw attention and receive the food. The adult that delivers the prey often makes crunching noises with its beak to indicate food has arrived before feeding the young.
The begging calls are an essential part of parent-offspring communication in peregrines. The vocalizations signal the chick’s hunger levels and let the parents know when more food is required. This ensures the fast-growing nestlings get adequate nutrition during this critical stage of development.
Fledgling Food Calls
As the nestlings grow older and prepare to fledge from the nest, their vocalizations change to more nasally food calls. These food calls serve a similar purpose as the begging calls but are given outside the nesting site as the newly fledged juveniles follow and trail after the adults.
Even at 4-6 weeks old, the young falcons still cannot hunt on their own and rely completely on the parents for food provisioning. The food calls allow the fledglings to keep signaling their need for food as they explore their surroundings away from the nest. It helps the parents continue to locate and feed the juveniles during the post-fledging period until they become independent hunters several weeks later.
Pair Duets and Courtship Screams
In addition to alarm calls and begging calls, peregrine falcons also vocalize as part of courtship and pair bonding behavior. Dramatic aerial screaming duets are made by breeding pairs, especially after pairing up during the pre-laying period. These duets consist of the male and female screaming back and forth at each other while performing acrobatic flight displays high in the air.
The duets help strengthen pair bonds between mates while also serving to delimit the territory. In some cases, the pair may even engage in food transfers mid-air as part of this aerial courtship screaming. Courtship duets also signal readiness for breeding and serve to synchronize the reproductive physiology between the male and female.
Outside of the main breeding season, peregrines may still occasionally perform courtship duets throughout the year, especially after reuniting with their mate after a period of separation. Even brooding females may initiate courtship screams from the nest ledge, with the male joining in from a distance perch. These maintenance duets help maintain the long-term pair bonds.
Fledgling Begging Screams
As the name implies, fledgling begging screams are the loud, raspy begging vocalizations given by young peregrines post-fledging as they chase after the adults demanding food. The fledglings tend to practice these loud begging screams most intensely between roughly 30-45 days after hatching as they perfect their flight skills but are still completely food dependent on the parents.
The jarring screams coincide with the late stage branching and fledgling dependency period when the juveniles are starting to venture further from the nest but still cannot hunt at all on their own. The demanding screams allow the dispersed fledglings to continue signaling their food needs from afar even as they spread out and follow the adults across the territory. These vocalizations are critical for soliciting the food the young falcons need to survive this vulnerable fledgling transition stage.
Conclusion
In summary, peregrine falcons have a wide repertoire of vocalizations that serve important functions related to territoriality, alarming others, begging for food, and pair bonding. Their conspicuous cries provide key social communication, allow coordination of behaviors, and help ensure the survival of both adults and young. The wide variety of alarm calls, food begging calls, courtship duets, and territorial vocalizations are all integral parts of peregrine falcon biology and behavior. Understanding why peregrines vocalize provides insight into their social structures and reproductive strategies. Their distinct cries will undoubtedly continue resounding across many landscapes where these resilient falcons live and breed.
References
[1] Ratcliffe, D. (1993). The Peregrine Falcon (2nd ed.). London: T. & A.D. Poyser.
[2] White, C. M., Clum, N. J., Cade, T. J., & Hunt, W. G. (2002). Peregrine Falcon (Falco peregrinus). In A. Poole (Ed.), The Birds of North America. Ithaca, NY: Cornell Lab of Ornithology.
[3] Nelson, R. W. (1970). Some Aspects of the Breeding Behavior of Peregrine Falcons on Langara Island, British Columbia. M.S. thesis, Calgary Univ., Calgary, AB.
[4] Ratcliffe, D. A. (1962). Breeding density in the Peregrine Falco peregrinus and Raven Corvus corax. Ibis, 104(1), 13-39.
[5] Sherrod, S. K. (1983). Behavior of fledgling peregrines. The Peregrine Fund, Ithaca, New York, USA.
[6] Inigo-Elias, E. E. (1996). A Comparative Study of Syllable Redundancy, Call Individuality and Classification in the Short Calls of Peregrine and Prairie Falcons. Boise State University, Boise, USA.
[7] Dicken, B.O. (2004). Biology of the Peregrine Falcon in Colorado. Master’s thesis, University of Colorado, Boulder, CO.
[8] Cade, T. (1982). Falcons of the World. Ithaca, NY: Cornell University Press.
[9] Juergens, M. (2002). Vocalizations of Bonelli’s Eagle during the postfledging dependence period. Journal of Raptor Research, 36(4), 298-304.
[10] Enderson, J. H. (1964). A Study of the Prairie Falcon in the Central Rocky Mountain Region. Auk, 81(3), 332-352.
Type of Call | Description | Context |
---|---|---|
Alarm call | Loud “kak-kak-kak” or “kek” sounds | In response to predators or threats |
Territorial call | Harsh screaming sounds | Warning away intruders |
Begging call | Short, repetitive cries | Given by nestlings soliciting food |
Fledgling food call | Nasally cries | Given by fledglings to request food |
Courtship duet | Dramatic screaming exchange | Strengthening pair bonds |
This table provides an overview of some common peregrine falcon vocalizations, describing the sound, context, and functional significance.
Interesting Facts about Peregrine Falcon Vocalizations
- Peregrines have at least 15 different identified vocalizations for communication
- The male and female make the same alarm and begging calls
- Courtship screams can be heard from over a mile away
- Begging call rates reach up to 400 cries per minute at peak hunger level
- The falcons make a tooth-clicking sound with their beaks when feeding nestlings
- Soft chittering vocalizations are made during peaceful perched interactions
- Young peregrines babble with peeping sounds when first learning to vocalize
- Adults go silent when stooping down to capture prey in order to not alert it
- High-pitched whines or squeals are given when peregrines are injured or captured
- Fledglings will give begging screams for up to 10 weeks before independence
These interesting tidbits help provide more insight into the diverse vocal repertoire and context of communication in peregrine falcons.
Evolutionary Explanations
Several evolutionary factors may help explain the development of complex vocal communication in peregrine falcons:
Warning Others of Shared Threats
Loud alarm calls that warn others of danger provide a mutual benefit by allowing all the falcons to take evasive action, improving survival odds for both the caller and receivers. Natural selection likely favored this signaling behavior.
Claiming Prime Nesting Sites
Territorial calls that proclaim ownership of high cliff ledges with good nesting spots give mating pairs exclusive breeding access to limited ideal real estate. Defending these prime sites helped reproductive success.
Coordinating Parental Care
Begging calls allow falcon chicks to effectively signal nutritional needs to prompt food delivery by parents. This enhances feeding efficiency and improves fledgling health and survival rates.
Maintaining Pair Bonds
Duets and courtship screams strengthen social ties between mates. Pair bonding facilitated higher breeding success and cooperation in raising young. Vocalizations thus became critical glue for the monogamous pair.
Reliance on Flight and Vision
As diurnal raptors that hunt using their incredible aerial abilities, vocal communication allowed peregrines to coordinate while out of direct line-of-sight contact. Vision and flight opened new avenues for vocal signaling.
Conclusion
In conclusion, peregrine falcons utilize a diverse repertoire of vocalizations for critical communication purposes. Loud alarm calls alert others to danger, territorial screams defend prime nesting real estate, begging calls request food, and courtship duets strengthen social bonds. Evolutionary selective pressures likely shaped these complex signaling behaviors to facilitate things like warning others of shared threats, claiming quality breeding sites, improving parental care, and maintaining pair bonds. The variety of peregrine falcon cries serve adaptive functions that are essential to the biology and ecology of these remarkable apex avian predators. Their wide range of vocalizations provide a window into understanding peregrine communication, social behavior, and reproductive strategies.