Smithornis

Smithornis
Grey-headed broadbill (Smithornis sharpei)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Eurylaimidae
Genus: Smithornis
Bonaparte, 1850

Smithornis is a genus of bird in the Eurylaimidae family. It contains the following species:

Lineage and Taxonomy

The genus Smithornis is a genus comprising three species commonly found in Africa. This genus was previously classified under the oscine flycatcher family (Muscicapidae) due to similarity prior to 1914.[1][2] By closer examination of the morphology and anatomical features of the genus resulted in a change in the classification from the Flycatcher family (Muscicapidae) to the African Broadbill family (Eurylaimidae). It is hypothesized that "Smithornis" belongs to a monophyletic genus in comparison to other broadbill species in the family Eurylaimidae. The differentiation occurred as a result of a division and diversification between Asian and African broadbills.[3]

Physiology

The species of "Smithornis" are unique in that they lack the vocal ability that many other birds possess. This differentiates the physiology of the syrinx or the vocal organ of the broadbill species. The anatomical features which stand out for Smithornis include the muscles in the syrinx. The muscle A1 is widened into a hammer shape and A2 is seen to be oblique.[4] They lack a pessulus which divides the tympaniform membranes and produces a song in other species of birds. They also lack intrinsic syringeal muscles which contract to change the song. Greenewalt 1968 hypothesized the "two voice" model in this genus which predicts that the lack of the two song vocal ability seen in other birds is due to the lack of a pessulus.[5]

Behavior

"Smithornis" are known for the rare ability to make sound with their wings. The typical behavior includes a short circular flight off of the perch and back on again. The vibration of the wings is used to make the sound.[6] This behavior is commonly seen in the early morning and late evening. It is predicted that this particular behavior is part of courtship to attract female broadbills. The male flashes a white patch on its back while making the klaxon-like sound as a reproductive display.[7][8] The sound is made by all species of "Smithornis" yet in S. "rufolateralis" only the male produces the sound and in S. capensis both the male and the females produce the sound.[9] An observation made in 1960 by Lawson described the behavior of two particular "Smithornis capensis". One individual flicked its wings to make the sound while another bird was close by. They flew near each other alternating turns making the sound. The observation described the behavior of the two birds as not aggressive yet thought to be connected with courtship.[10]

Smithornis capensis capensis 1838
SmithornisRufolateralisWolf

It was previously assumed that the sound was produced by the long outer 9th and 10th major convert feather.[11] A recent scientific study investigated the source of the klaxon-like sound the wings produce by testing the sound-making ability of two species of "Smithornis", S. "rufolateralis" and S. "capensis". The researchers used synchronized high speed video and sound recordings to analyze the behavior. The video and recordings of the species in flight allowed the researchers to see the exact moment in the circular flight in which the sound is produced. They discovered that it was not the P9 and P10 feathers producing the sound but the P6 and P7 feathers.[12]

References

  1. ↑ Chapin, James P. The Birds of the Belgian Congo: Part 3. Vol. 75A. New York: Bulletin of the American Museum of Natural History, 1953. Print.
  2. ↑ Prum, Richard O. "Phylogeny, Biogeography, and Evolution of the Broadbills (Eurylaimidae) and Asities (Philepittidae) Based on Morphology." The Auk 110.2 (1993): 304-24. JSTOR. Web.
  3. ↑ Prum, Richard O. "Phylogeny, Biogeography, and Evolution of the Broadbills (Eurylaimidae) and Asities (Philepittidae) Based on Morphology." The Auk 110.2 (1993): 304-24. JSTOR. Web.
  4. ↑ Prum, Richard O. "Phylogeny, Biogeography, and Evolution of the Broadbills (Eurylaimidae) and Asities (Philepittidae) Based on Morphology." The Auk 110.2 (1993): 304-24. JSTOR. Web.
  5. ↑ Greenewalt, Crawford H. Bird Song: Acoustics and Physiology. Washington: Smithsonian Institution, 1968. Print.
  6. ↑ Bates, G. L. "Some Facts Bearing on the Affinities of Smithornis." Ibis 56.3 (1914): 495-502. Web.
  7. ↑ Bates, G. L. "Some Facts Bearing on the Affinities of Smithornis." Ibis 56.3 (1914): 495-502. Web.
  8. ↑ Clark, C. J., A. N. G. Kirschel, L. Hadjioannou, and R. O. Prum. "Smithornis Broadbills Produce Loud Wing Song by Aeroelastic Flutter of Medial Primary Wing Feathers." Journal of Experimental Biology 219.7 (2016): 1069-075. Web.
  9. ↑ Chapin, James P. The Birds of the Belgian Congo: Part 3. Vol. 75A. New York: Bulletin of the American Museum of Natural History, 1953. Print.
  10. ↑ Lawson., W. J. "Probable Courtship Behaviour Of The Broadbill Smithornis Capensis." Ibis 103a.2 (2008): 289-90. Web.
  11. ↑ Clark, C. J., A. N. G. Kirschel, L. Hadjioannou, and R. O. Prum. "Smithornis Broadbills Produce Loud Wing Song by Aeroelastic Flutter of Medial Primary Wing Feathers." Journal of Experimental Biology 219.7 (2016): 1069-075. Web.
  12. ↑ Clark, C. J., A. N. G. Kirschel, L. Hadjioannou, and R. O. Prum. "Smithornis Broadbills Produce Loud Wing Song by Aeroelastic Flutter of Medial Primary Wing Feathers." Journal of Experimental Biology 219.7 (2016): 1069-075. Web.
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