Seminars in Hearing Research at Purdue (SHRP)

Title:  The geographical properties of chickadee song: our birds are truly weird

Speaker(s): Jeffrey R. Lucas, Ph. D., Professor, BIOL

Date: Oct 03, 2019
Time: 10:30 – 11:20 am
Location: LYLE 1150

Abstract:

There are two chickadee species in Indiana: black-capped north of South Bend, and Carolina everywhere else. Black capped chickadee song is a two-part song with a glissando followed by a pure tone. The glissando frequency is variable within individuals, but the ratio between the glissando and pure-tone frequencies tend to be fixed. Male quality is indicated by how variable the ratio is for all the songs a male sings. Little is known about similar properties of Carolina chickadee (CACH) song, though data published to date on CACH song recorded along the east coast from Pennsylvania to South Carolina suggests that there is no selection on the ratio and no tight transposition of frequencies, a conclusion backed up by playback studies. However, pitch sifts may be important in Indiana CACH song. We quantified song properties from 7 sites across Indiana. Indiana song appears to be truly weird relative to CACH song recorded throughout the rest of the geographical range of the species. CACH song is typically 4 notes with some dialectal variation. Song repertoires differed among the 7 sites and the role of frequency in song production also appears to be population/culture specific. Simple pitch shifts in only part of the song were observed for the most common song type in 3 sites. True frequency transposition was found in 2 other sites. Songs of birds from the 6th site are more variable and lacked true pitch shifts. Songs from the 7th site indicate a continuous transposition of frequencies. Thus the role of song frequency, along with song syntax, in song complexity appears to be subject to local levels of cultural evolution.

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The working schedule for this semester is listed here:

https://purdue.edu/TPAN/hearing/shrp_schedule

The titles and abstracts of the talks is listed here:

https://purdue.edu/TPAN/hearing/shrp_abstracts