Please consider joining us on Saturday, March 12th at 9am to hear from long-time Bird Club member Ron Bradley! To learn more about our Live to Learn speaker series or register for upcoming talks, click here.
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Our speaker is: Dr. Jeffrey Lucas, Purdue University Topic: What we miss when we listen to bird song: the hearing side of avian communication. This meeting will be held in person at DHNC. Light refreshments provided. Our guest speaker will be joining us via Google Meet. Bird Club members are welcome to attend the meeting virtually if they are unable to attend in person. Meeting link: To join the video meeting, click this link: https://meet.google.com/xwa-ozcx-jbp Otherwise, to join by phone, dial +1 336-904-9307 and enter this PIN: 178 309 758# To view more phone numbers, click this link: https://tel.meet/xwa-ozcx-jbp?hs=5  Description:
What we miss when we listen to bird song: the hearing side of avian communication Jeff Lucas Dept of Biological Sciences Purdue University West Lafayette IN Birders use spectrograms to help them understand bird song. When doing so, we implicitly assume that birds are hearing what we see in the spectrogram. If so, then we’d expect that details of how birds hear should match details of their song properties, and they often do. For example, tufted titmice use very high frequency alarm calls and indeed have very good high frequency hearing. Similarly, birds with very tonal song (e.g. titmice) are not very good at processing rapidly changing frequencies, but birds with very rapid elements in their song (e.g. white-crowned sparrows) are better than you are at processing rapid frequency changes (!). Birds (and all other vertebrates) are also able to retune their auditory system across seasons. Comparisons of their song with auditory performance suggest that they retune their auditory system in the breeding season to extract song properties at enhanced levels. For example, Carolina chickadees have a broad-band song that matches the upregulation of processing of a wide range of tones in the breeding season. In contrast, white-breasted nuthatches have a song with maximum intensity at about 2 kHz, and their auditory system only gets better at 2 kHz during their breeding season. We tested this further with 9 sparrow species that vary in habitat preference and song properties. The song properties are not shared between related species, but they are strongly affected by habitat. Open adapted species tend to have rapid, high frequency songs whereas closed-canopy species tend to have low-frequency tonal songs. Oddly, there was no correlation between habitat and the range of frequencies they hear well. Surprisingly, we found that song type (trill vs more complex notes) correlated strongly with hearing properties – the implication is that the properties of trills are processed very differently than the properties of more complex songs (say of song sparrows). These data on sparrows suggest that the spectrogram does not tell the whole story. Which makes bird song all the more interesting! |