The white breasted cormorant (Phalacrocorax melanoleucos) is a large aquatic bird found across parts of Asia, Africa, Australia and New Zealand. It is known for its distinctive white throat and breast feathers. The white breasted cormorant has a range of vocalizations used for communication. Its most well-known call is a loud, deep, guttural croak. This article will provide an in-depth look at the call of the white breasted cormorant, including what it sounds like, the context in which the bird uses its call, and how the call functions in communication and social interactions. Keep reading to learn all about the fascinating vocalizations of this remarkable waterbird!
What Does the Call of the White Breasted Cormorant Sound Like?
The most notable vocalization of the white breasted cormorant is a loud, low-pitched croaking sound. This guttural croak is deep and raspy, often sounding hoarse or cracking. It has been described as similar to the croak of a raven or crow. Here are some key features of the white breasted cormorant’s distinctive call:
– Low pitch – The croak is very low in frequency, with a bass, resonant quality.
– Harsh timbre – The call has a rough, abrasive edge to its sound. This is what produces the guttural, raspy effect.
– Croaking repetition – The bird’s call consists of a series of croaks, usually given in quick succession at a regular pulse.
– Loud volume – The croaking call is loud, able to carry over long distances. It can reach volumes of up to 100 decibels.
To get a good sense of what this unusual vocalization sounds like, listen to audio recordings of the white breasted cormorant’s call online. It has an unmistakable guttural, croaking quality that stands out from the calls of other waterbirds. The staccato, rhythmic delivery of the croaks is also unique to this species.
When and Why Does the White Breasted Cormorant Call?
The white breasted cormorant uses its signature croaking call in a number of different contexts. Some of the main situations when the bird vocalizes include:
– Claiming nest sites – The male will make loud croaking calls from potential nesting spots to proclaim ownership and dissuade rivals.
– Strengthening pair bonds – Mated pairs call back and forth to each other to reinforce their bond. This is especially common during nest preparation.
– Warning threats – The cormorants give alarm calls when threatened by predators or intruders near their nesting colony.
– Begging for food – Chicks croak loudly and insistently when begging for food from their parents.
– Communicating location – Adults use contact calls to reveal their whereabouts to their mate or offspring. The calls help birds keep track of each other.
– Defending territory – Croaking is used to ward off trespassing birds from feeding and nesting areas. It also signals territorial boundaries.
So in summary, the signature call of the white breasted cormorant plays an important role in breeding activities, parent-offspring interactions, territorial behaviors, and threat response. It allows these highly social birds to communicate and coordinate essential activities in their colony.
Unique Features of the Call
The white breasted cormorant’s croaking vocalization has some special attributes and features that help the call perform its functions:
– Carrying power – The loud, low-frequency call can travel long distances of over 1 km. This helps connect distant birds in the colony.
– Individual uniqueness – Subtle differences in call pitch and hoarseness distinguish individual birds. This helps mates and chicks identify each other.
– Coded messages – The number and rhythm of croaks conveys specific information about context and meaning.
– Seasonal changes – The male’s call gets lower and louder during breeding season to attract mates and warn rivals.
– Begging calls – Chicks incorporate higher, more urgent notes and repetitive croaking when begging for food.
– Group chorus – Many birds croaking together results in a booming chorus that establishes territory.
– Durability – Cormorants can make the call continuously for long periods without tiring or damaging their vocal cords.
These special properties allow the white breasted cormorant’s call to function well in social communication despite its harsh sound. The bird relies on this hardy vocalization to coordinate its colonial nesting lifestyle.
How the Call Develops in Young Birds
The distinctive croaking call of the white breasted cormorant doesn’t emerge fully formed when birds first hatch. Young cormorants go through several stages of vocal development:
– Newly hatched chicks – Make high-pitched peeping calls to beg for food from parents.
– One month old – Begin making very crude, muted croaking sounds to communicate with parents.
– Two months old – Croaks develop a raspy, hoarse quality but still lack volume and depth.
– Three months old – Call grows louder, deeper, and more guttural, akin to juvenile “puberty” in voice.
– Five months old – Fledglings can make the full adult croak, used to beg for food from parents after leaving the nest.
– One year old – Juveniles birds develop the full adult repertoire of calls used for breeding and colonial communication.
So the iconic guttural croak of the cormorant emerges as the chick grows and requires more sophisticated vocalizations for adult colonial living. It takes about a full year for the juvenile to master the range of adult calls.
How Does the Call Vary Between Populations?
The white breasted cormorant has an extremely wide global distribution across Australasia, Asia, and Africa. This extensive range contains several distinct subspecies and populations. There are some subtle but noticeable differences in the croaking vocalizations between these populations:
– Australasian birds – Lower average pitch, more rapid croaking tempo.
– Indian/Sri Lankan birds – Slightly higher pitch, hoarser tone, slower tempo.
– Southern African birds – More drawn out, bellowing croaks in choruses.
– Madagascar birds – Shorter, more abrupt croaks with an almost staccato-like rhythm.
– New Zealand birds – Very deep, throaty croaking with a pulsing, resonant quality.
Scientists think local environmental conditions and lack of mixing between distant populations has caused these variations to arise. However, all the core features of volume, guttural tone, and repetitive croaking remain consistent across the cormorant’s global range.
How Does the Call Compare Between Males and Females?
There are some slight differences between the calls of male and female white breasted cormorants:
– Males typically have lower-pitched croaks than females.
– Males vocalize more often, especially long bouts of calling during courtship and mating.
– Male calls tend to be louder and more aggressive, warning off rivals.
– Female calls are often used for locating mates and offspring.
– Females make more food-begging calls of longer duration towards males.
However, both sexes are capable of making the full repertoire of calls as needed in all contexts. The main variation is increased use of territorial and courtship vocalizing in males. Female calls converge more on maintaining pair bonds and communicating care-giving. But overall, the calls sound very similar between the sexes.
How Does the Cormorant Produce Its Call?
The white breasted cormorant has specialized anatomical adaptations to produce its loud, guttural croaking call:
– Large syrinx – This vocal organ sits at the juncture of the trachea and bronchi. Vibrating tissues in the syrinx modulate airflow to create sound.
– Expandable throat pouch – The gular pouch on the throat can be inflated to amplify and resonate the call.
– Stout tracheal rings – These reinforce the windpipe while allowing it to elongate during gular inflation.
– Thick tracheal muscles – Strong muscles control air flow and tension on the syrinx to modify pitch and volume.
– Small head – Keeps the vocal tract short, boosting resonance of low frequency sounds.
Combined with its large chest muscles and long neck, this anatomy allows the cormorant to make sustained, penetrating calls that carry far over water. The expansive throat pouch gives the call its booming, croaking quality. It’s a highly specialized system tailored for noisy colony life.
How Do Humans Perceive the Call?
The loud, jarring croaks of the white breasted cormorant elicit mixed responses in human listeners:
– Discomfort – Many people find the harsh, grating quality of the call unpleasant or annoying at close range. The volume can be overwhelming.
– Curiosity – The unusual guttural sound often piques interest from birdwatchers and nature lovers. The call is unlike any other waterbird vocalization.
– Concern – Constant croaking in a colony is sometimes perceived as a nuisance by nearby residents. But this is just normal social behavior for cormorants.
– Connection – For some listeners, the wild croaking evokes a sense of connection to untamed nature. The call transports the imagination to the cormorant’s watery world.
– Warning – Ancient mariners took the croaking as an ominous sign of bad weather approaching, associating the noise with storms and high seas.
So the reactions are complex, with elements of intrigue and annoyance. But most agree the white breasted cormorant’s call is a wild, unforgettable sound of the aquatic realm.
Conclusion
The white breasted cormorant’s guttural croaking call has fascinated and confounded humans across this waterbird’s wide range. With its raspy, resonating quality and carrying power, the call is a vital tool for communication and social cohesion in the species’ large nesting colonies. Each croak contains coded information about identity, needs, threats, and territory. The development and learning of these vocalizations in young cormorants allows the ancient lineage’s noisy, crowded colonies to thrive. While the sound may grate on some ears, it represents the wildness of wetlands and reveals the hidden social world of the white breasted cormorant. For those willing to listen closely, it tells a vivid story of aquatic life.