Researchers studying African penguin communication have found that these birds use six different vocalizations, or calls, in order to convey feelings such as hunger and aggression. According to the study, which has been published in PLOS ONE, four of the calls are used exclusively by adults, whereas the other two are only used by juveniles and chicks.
African penguins are highly sociable animals notorious for their distinctive, donkey-like squawks which have earned them the nickname “jackass” penguins. Researchers are interested in these vocalizations because they can provide us with a lot of information, such as age, behavioral state, condition and relationships with others. Furthermore, classifying them can also assist in the planning of conservation strategies.
While researchers had previously provided basic descriptions of African penguin calls, little was known about the meaning behind their characteristic haws and brays. Moreover, the majority of prior research had focused on Antarctic and sub-Antarctic species such as Emperor penguins, neglecting temperate species.
To fill in gaps in our knowledge, University of Turin researchers spent 104 days collecting both audio and video recordings from a captive colony of jackass penguins in a zoo in Italy. They then analyzed and categorized these calls and matched them up to the behavioral contexts in which they were produced.
Of the four different vocalizations identified in the adults, two were short, single-syllable calls. One was a contact call produced by isolated birds and the other was an agonistic call used in spats or confrontations. The other two vocalizations were display songs; one was a mutual display song emitted by nesting partners and the other was an ecstatic display song, which was the loudest and longest of all the calls.
They also identified two distinctive begging calls uttered by chicks and juveniles. The first was a series of short cheeps referred to as “begging peeps,” which signal to the parents that the chick wants feeding. The second call, used by unweaned juveniles, was dubbed a “begging moan" and was also used as a request for food.
While studying penguins in captivity has its advantages, such as reducing ambient noise, the researchers accept that there may be vocalizations used in the wild that these particular birds do not display. Still, this research should help to standardize known vocalizations and also increases our understanding of these animals.
“Vocal communication allows us to understand the many different aspects of the biology of this species,” lead author Livio Favaro told the Guardian. “Penguins have less sophisticated vocal mechanisms compared to song birds, but they have very sophisticated mechanisms to encode information in songs.”
Habitat loss, egg collection and environmental pollution have collectively caused a sharp decline in African penguin numbers over recent years and they’re now listed as an endangered species. Understanding penguin vocalizations could ultimately lead to a simple way to track and estimate populations, which will hopefully assist conservation and management strategies.
[Header image "African Penguins," by Wildlife Wanderer, via Flickr, used in accordance with CC BY-NC-ND 2.0]