Types of Songs and Calls:
For such a large bird, the Bald Eagle’s voice is surprisingly weak. Its call is compared to a snickering laugh and consists of seven or eight notes sounded quickly and haltingly in a way that sounds very labored. It can be written to sound like ki-ki-ki-ki-ki-ki-ker (Stalmaster, 1987). The function of this strange vocalization is unknown so further research on the function of the vocalization is needed. Young Bald Eagles make different sounds than the adults. After hatching, the nestlings make a single- note tonal peep (Gilbert et al., 1981). As the bird ages, its sounds become more complex and have a greater volume variance and by day thirty of their life their call has similar characteristics to the adult Bald Eagles call even though there is no direct evidence that offspring learn their calls from adults (Buehler, 2000). Since there is no direct evidence, further research is needed to determine whether Bald Eagle song is learned or innate. To test this, scientists could raise a Bald Eagle in captivity without interaction with any other birds. They could then observe whether this Bald Eagle grew to have the same call as other adult Bald Eagles or if it was different or if it did not learn a call at all. The cheeping call of the nestling serves as a way to beg for food, an alarm call, and a communication with adults (Kussman, 1977). After four weeks, the young Bald Eagles also develop wail and Peal calls. The peal call is often given in response to humans approaching the Bald Eagles and is a high-pitched cry that has three to five notes that sound like a gull followed by six or seven rapid notes. This peal is described to sound like, kwit-kwit-kwit-kwit-kee-kee-kee-kee-ker (Buehler, 2000). Another unique call the the Bald Eagle is the call that females make when they are ready to mate. This sound is soft and high-pitched and repeated multiple times. The male also has a unique call that serves as a defense mechanism, it is a high-pitched peal to signal when other birds or humans approach. They will use this to fend off attacks at communal feeding sites also (Buehler, 2000).
Song Sonograms/Sound File:
A. is the adult chatter call of the Bald Eagle. B. Is the adult scream call.
Sound files can be accessed at :http://www.allaboutbirds.org/guide/bald_eagle/sounds
Dialect: Very little is known about Bald Eagle dialect. Since Bald Eagles live in many different places, it could be inferred that each region of Bald Eagles has its own distinct dialect (Eakle et al., 1989). To test this theory, scientists could observe Bald Eagle populations in different areas of the world. They could make sonograms of the songs in the different areas then they could take those sonograms and compare them to determine if the sonograms vary by region that the bird lives.
After hatching, the vocalizations produced by the Bald Eagle is a single toned peep, with little change in frequency. Cheeping is used early in life to communicate with adults if the bird is frightened or feels in danger (Buehler, 2000). By day 30, the call has many characteristics of an adult, and is fully developed at four weeks post-fledgling (Gilbert et al., 1981). Experiments done on Bald Eagles suggest that birds raised in acoustic isolation produce atypical songs in their adult stages (Eakle et al., 1989). This leads many scientists to believe that the song of the Bald Eagle is learned early in life, during a particularly sensitive period in their development. This song learning is similar to most species that are passerines. Sonograms recorded of the Bald Eagle show variance year to year, which also suggests song learning from the parents (Buehler, 2000).
Buehler, David A. 2000. Bald Eagle (Haliaeetusleucocephalus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online:http://bna.birds.cornell.edu/bna/species/506doi:10.2173/bna.506
Eakle, W.L., Mannan, W.R., Grubb, T.G. 1989. Indentification of Individual Breeding Bald Eagles by Voice Analysis. The Journal of Wildlife Management 53: 450-455.
Gilbert, S., P. Tomassoni, and P. A. Kramer. 1981. History of captive management and breeding of Bald Eagles. Int. Zoo Yearb. 21:101-109.
Kussman, J. V. 1977. Post-fledging behavior of the northern Bald Eagle, Haliaeetus leucocephalus, in the Chippewa National Forest, Minnesota. Phd Thesis. Univ. of Minnesota, Minneapolis.
Stalmaster, M. V. 1987. The Bald Eagle. Universe Books, New York