The Laughing Kookaburra

(Dacelo Novaeguineae)

What is a Kookaburra?

 

Standing at approximately one and a half feet tall, the Laughing Kookaburra is the largest member of the kingfisher family.  Female kookaburras tend to be larger than the males, revealing an interesting reverse sexual dimorphism, and can weigh up to two pounds.  Their “dagger-like” beaks can reach four inches in length (Freedman, 2004; National Geographic).  It has been suggested that, due to their smaller size, males may be more efficient at hunting and provisioning (Legge & Cockburn, 2000), duties which often fall on them. Distinctive not just in size but in appearance as well, the kookaburra is typically seen with dark brown plumage, brown stripes across its eyes, white along its underbelly and head, a reddish-brown and black stripped tail, and a black beak (National Geographic).  Although it is unknown what adaptive purpose it serves, the three front toes of kookaburras are fused together (Freedman). Unlike many birds of its kind, the kookaburra has not be negatively affected or threatened by the encroachment of humans onto its territory.  In fact, they seem to have actually benefited from the artificial territories, such as gardens and parks, which have been created by humans (ed. Hutchins).

The Song

Affectionately called the “Laughing Jackass” by residents of Australia, the kookaburra is most commonly known for its unique call.  The hours during which their song can be heard are so predictable that another nickname given to the kookaburra is the “Bushman’s Clock”, as they tend to sing in both early morning and dusk. (Encyclopedia Britannica).  Described as a “nasal whining” by some (Encyclopedia of Animals), and “loud,” “rollicking,” and “maniacal” by others (Perrins, 1990), there is little disagreement  among listeners regarding the similarity of the kookaburra’s call to human laughter.  The song is usually started by the dominant male of the group, and it gradually becomes louder as other members join together in a chorus.  The song appears to serve the purpose of alerting other kookaburra’s in the area of a particular group’s presence, as well as acting as a deterrant to the encroachment upon this group’s territory. It may also be a way of communicating information regarding the approximate size and location of a group to others (Baker, 2004). Some researchers believe that, as part of territorial defense, helpers may join the dominant pair in singing their characteristic song (Legge & Cockburn).  Perhaps this increase in volume is more intimidating to outsiders because it suggests that a larger group is nearby. As multiple kookaburra groups in a particular area can often be heard vocalizing very distinctive, overlapping songs, some researchers speculate that the calls are either taught to offspring by parents or are determined by the genetics of specific kin groups (Baker).