Research
When you walk down a hall, the familiar sounds of your own footsteps provides a simple observation: locomotion generates sound.
Animal Aeroacoustics
Courtship and Locomotion
Evolution of Behavior
Animal Aeroacoustics
We investigate the physical mechanisms by which air flowing over a feather or wing generates sound. Mechanisms include aeroelastic flutter, in which a feather oscillates at a stable frequency set by both its resonance frequency and the airflow.
We have in the lab:
An Acoustic wind tunnel (open jet, so that microphones can be out of airflow)
An acoustic cameras (localizes sound sources)
High speed cameras
Species studied:
Hummingbirds (hummingbirds are our specialty)
Great Gray Owl (collaboration with Jim Duncan in Manitoba)
Nightjars (collaboration with Nacho Areta in Argentina)
Flycatchers (collaboration with Nacho Areta in Argentina; also with Valentina Gómez-Bahamón.
Smithornis Broadbills in Africa
We are broadly interested in the physical acoustic mechanisms in play on animal wings, and how these sounds get converted into signals, or suppressed (in the case of quiet flight)
Courtship and Locomotion
We also study courtship display performance in its own right. Males of taxa such as hoverflies or hummingbirds attain high velocities, accelerations, or wingbeat frequencies in their aerial displays. We posit such behaviors become exaggerated through directional female preference for a dynamic male feature, similar to how female preferences for static features are thought to give rise to exaggerated morphology such as the elongated tails of birds or fish (Clark 2009; Clark 2012).
Research questions include:
Why do some hummingbirds nearly double their wingbeat frequency during displays?
What limits display performances?
How do males differ in their ability to perform displays?
Courtship displays can feature extreme behavioral performances not easily observed in other experimental contexts, and thus make interesting case studies of extreme performance per se.
Evolution of Behavior
Hummingbird courtship displays are also fascinating from the perspective of behavior. Over the past decade I have conducted fieldwork in ~13 countries in North Central and South America, most recently including Cuba and Argentina, trying to obtain display descriptions from every species in the Bee Hummingbird (Mellisugini) clade. Thus far this project has been descriptive:
Described new displays
Described new hybrid combinations
Split one hummingbird species into two
But we now have enough data that the bigger picture is now emerging. In the next few years we will use our data to examine:
How tail sounds coevolve with behavior
How behavioral components ('elements') of displays evolve
How nonvocal sounds coevolve with vocalizations
The role of Song Learning
Hybrid hummingbird-finder (and lab tech) David Rankin and I are investigating the phenotype of rare hummingbird hybrids such as Anna's x Allen's, Anna's x Costa's, and Black-chinned x Allen's that we have found in Riverside. David has found 5 such hybrids on and around the UCR campus in the past year alone.
Allen's x Rufous hybrid zone: we found a hybrid zone between Allen's and Rufous Hummingbirds, which we described in 2019 (Myers et al 2019). The hybrid phenotypes are quite interesting, since the displays that the two parent species perform are rather different. In collaboration with Alan Brelsford (UCR) and Kevin Burns (SDSU).
Other Projects
We have large outdoor aviaries and permits to work with hummingbirds. On campus we have Anna's, Costa's and Allen's hummingbirds year-round, plus Black-chinns from April-Sept. I'm happy to collaborate with anyone wanting to take advantage of these resources.
Ongoing projects include:
Pollination biology (in collaboration with Erin Rankin (Entomology, UCR)