Baltimore Oriole (Icterus galbula): Singing Behavior
By: Rhea Randhawa and Elizabeth Ralston
Types of Songs and Calls:
The Baltimore Oriole (Icterus galbula) has a distinctive song that stands out among other birds due to its vigorous and harsh nature. Songs are extremely variable- each bird has its own slight variation of the basic Baltimore Oriole song. The song generally has around 6 syllables, and the pitch of the each note usually is inflected sharply downwards. The song can also be as simple of one or several notes of the same pitch. Songs can vary from ⅘ ths of a second to 2 ⅗ ths of a second.
Baltimore Orioles also make several types of call. One call used by both male and female orioles is the “chatter call”, which is a series of 2-30 repetitions of the same call figure. It is commonly used for aggressive interactions, both male-male, female-female, and interspecies. (Beletsky, 1982) The first vocalization produced by the Baltimore Oriole is the begging call, which young orioles produce in the nest in order to signal to the parents that they are hungry, and which consists of strings of two sharp notes. (Bent, 1958)
Although in most songbird species it is the male that does the majority of the singing, however female Baltimore Orioles have singing abilities nearly comparable to their male brethren. Female song resembles that of males in frequency, duration and song figure duration. However, female Baltimore Orioles rarely share song figure duration with their mates, indicating that mates have differing songs. It has been suggested by some researchers that male-female song is used for pair-bond maintenance, as there have been some accounts of Baltimore Orioles singing “duets”. (Beletsky, 1982) Vocal duetting is when two birds, usually a mated pair, produce temporally coordinated vocalizations in which certain parts of the repertoire overlap. Approximately 3-4% of species worldwide produce duets. Baltimore Orioles are the only North American Oriole species know to duet. (Benedict, 2008)
In studies of tropical orioles, it was found that while males sing solos at a high rate during the breeding season, females sing at varying rates all year around. Duets occur all year, but are more common in the non-breeding season. Males singing more in the breeding season supports the hypothesis that male song is sexually selected, however the fact that female orioles sing solos suggests that female song is not exclusively tied to breeding purposes. (Odom, 2016)
Song Sonograms / Sound file:
Songs of male and female Baltimore Orioles (Beletsky, 1982)
There have been no studies done on the existence of dialects in Baltimore Orioles. As certain studies have suggested that Baltimore Orioles acquire through learning, it would also be likely that dialects would exist, but more research needs to be done on this topic. (Birds of North America)
The way that Baltimore Orioles acquire song is currently unknown, although some studies have been done on the matter. One such study found that Baltimore Orioles, when hand-reared and not exposed to any song early in life developed different songs from wild orioles. These hand-reared orioles infrequently produced abrupt one-note songs, and in the spring began producing longer, complex and varied songs which never fully developed into the typical song of an adult oriole. (William, 1901) This data would indicate that Baltimore Orioles do in fact learn their song, as birds isolated from song tutors failed to learn the song of their species. However, it also demonstrates the ability for Baltimore Orioles to produce their own song, which helps to explain why Baltimore Oriole song is so varied between birds.
The song of Baltimore Orioles and other orioles evolves rapidly, indicated by a pattern of many recent changes in song. There has been no relationship demonstrated between song characteristics and genetics. Because there is no link between genetics and song characteristics, learning is likely how Baltimore Orioles acquire their song. (Price, 2007)
However, contrary to the understanding that song evolves more rapidly then calls, a study done on tropical orioles found that the divergence between the calls of two related species was greater than the divergence between the songs of two related species. This could suggest that differing calls prevent interbreeding. It could also suggest tutor based learning- as the songs of two tropical oriole species were almost identical, it is possible that interspecies learning occurred where the two species shared a range. (Sturge, 2016)
Questions for Future Study:
Not much research has been done on the vocalizations of baltimore orioles, with research rather being focused on tropical oriole species. There has been no research done on the existence of dialects in Baltimore Orioles, which could be a fascinating study. A field study could be done, collecting and comparing song samples from various geographical regions.
Furthermore, it would be helpful for more in depth studies to determine whether Baltimore Orioles learn, and how they learn. A controlled experiment could be done using hand-reared birds and song playback in order to determine the learning abilities of these birds.
Beletsky, L. (1982). Vocalizations of Female Northern Orioles. The Condor, 84(4), 445-447. doi:10.2307/1367454
William E. D. Scott. (1901). Data on Song in Birds. Observations on the Song of Baltimore Orioles in Captivity. Science, 14(353), 522-526. Retrieved from http://www.jstor.org/stable/1629781
Price, J. J., Friedman, N. R. and Omland, K. E. (2007). SONG AND PLUMAGE EVOLUTION IN THE NEW WORLD ORIOLES (ICTERUS) SHOW SIMILAR LABILITY AND CONVERGENCE IN PATTERNS. Evolution, 61: 850–863. doi:10.1111/j.1558-5646.2007.00082.x
Benedict, L. (2008). Occurrence and life history correlates of vocal duetting in North American passerines. Journal of Avian Biology, 39: 57–65. doi:10.1111/j.0908-8857.2008.04103.x
Bent, A. C. (1958). Life histories of North American blackbirds, orioles, tanagers, and their allies. U.S. Natl. Mus. Bull. no. 211.
Odom K. J., Omland K. E., McCaffrey D. R., Monroe M. K., Christhilf J. L., Roberts N. S., Logue David M. (2016) Typical Males and Unconventional Females: Songs and Singing Behaviors of a Tropical, Duetting Oriole in the Breeding and Nonbreeding Season. Frontiers in Ecology and Evolution, https://www.frontiersin.org/articles/10.3389/fevo.2016.00014/full
Sturge, R. J., Omland, K. E., Price, J. J. and Lohr, B. (2016), Divergence in calls but not songs in the orchard oriole complex: Icterus spurius and I. fuertesi. J Avian Biol, 47: 109–120. doi:10.1111/jav.00595