Robert Dudley, Professor

Closed (2) Hummingbird Dietary Preference for Fermented Nectar

Closed. This professor is continuing with Spring 2021 apprentices on this project; no new apprentices needed for Fall 2021.

Nectar-feeding birds are naturally exposed to low levels of ethanol given the ubiquity of fermenting yeast within nectar. However, their possible preference to consume ethanol-containing solutions has never been investigated. This project will use binary-choice behavioral feeding trials with ethanol/sucrose solutions containing up to 3% ethanol to determine if hummingbirds prefer to consume fermented relative to non-fermented nectar.

Duties for the Undergraduate Apprentice will include monitoring captive hummingbirds, conducting behavioral choice experiments, compiling data, and writing a report. Learning outcomes will include increased familiarity with methods of experimental design and data analysis, training in how to write a scientific paper for publication, and increased conversancy with concepts in animal behavior and physiology.

Day-to-day supervisor for this project: Ashley Smiley, Staff Researcher

Qualifications: Required: Completion of introductory biology courses, ability to download and analyze scientific articles using Google Scholar. Desired: Knowledge of physiology and ornithology. Applicants are encouraged to submit their application along with a short statement that includes any background relevant for this position, along with a current transcript and curriculum vitae.

Weekly Hours: 6-8 hrs

Related website:

Closed (3) How do arboreal lizards glide?

Applications for fall 2021 are now closed for this project.

Any organism that lives in a tree risks falling to the ground. There are many consequences that an organism might face if this were to happen, such as injury or death upon impact with the ground or dangerous encounters with other organisms. As a result, many arboreal organisms have means to influence their body orientation and trajectory as they fall so as to control their descent and minimize the negative repercussions. This project seeks to understand the biomechanics of controlled aerial descent in arboreal lizards by using high-speed videos to record and track the movements of these lizards while gliding. I simulate gliding in lizards by using a vertically-oriented wind tunnel. Even though these organisms lack dedicated airfoils, they still have substantial control of their fall. Understanding such a system may lead to insights regarding the origin of flight in vertebrates.

Tasks: The apprentice will assist in processing 3D data captured from videos of lizards in order to reconstruct the positions of the lizards and their body parts during the glide.

Learning Outcomes: The apprentice will learn how to create three-dimensional reconstructions of video data as well as basic knowledge of how to operate the computer software that we use to do so. The apprentice will also gain experience in collaborating with biologists as well as knowledge in the subjects of biomechanics and morphology.
, Graduate Student

Qualifications: Required: Attention to detail, patience, and both good organization and time-management skills. Also a genuine interest in the subject matter. Applicants are encouraged to submit the application with short statement that includes any background that may be relevant for the position. A current transcript, schedule, and CV may be requested by e-mail.

Weekly Hours: 6-8 hrs

Related website:

Closed (4) Hummingbird Flight Performance in the Tropics

Closed. This professor is continuing with Spring 2021 apprentices on this project; no new apprentices needed for Fall 2021.

A basic question in the field of biomechanics is: how does size affect movement? Size variation in living organisms today covers a range of 21 orders of magnitude! Size can dictate how an organism occupies space in its ecology and it can impact pace of life and reproduction. Size particularly impacts mode of flight for volant vertebrates. A California condor weighing 10.5 kilograms is obligated to soar while an Anna’s hummingbird weighing 4.5 grams can hover at 40 cycles per second. An intra-class comparison of condors and hummingbirds offers a coarse-grained look at how size may impact movement. Shifting to a finer-grained scale we have a lot to gain in our understanding of the size effects on flight from quantifying the movement of more closely related animals that vary in body size. Quantifying movement gives us a measure of performance, which can then be compared between members of the same species or amongst different species.

The family of hummingbirds, Trochilidae, is an ideal focal taxon to investigate flight performance. Tropical hummingbirds are rich in diversity with just over 350 species and varying from 2 grams to just over 20 grams in size. Our study site is in the country of Colombia where we have filmed hummingbirds in various experimental treatments to collect data that we can analyze here in Berkeley. Borrowing a few principles of biomechanics we can make predictions about how size affects flight performance. We test these predictions by measuring performance in less than 10 species of hummingbirds found in Colombia.

Students will spend the majority of time with image analysis including digitization (R, MATLAB) of high-speed video (Phantom, Fastec, and Hispec cameras filming at 1,000 fps), morphological analysis of images of hummingbirds (Image J), and qualitative analyses of hummingbird flight behavior. Students will gain experience with image digitization and reconstruction of free-flying wild hummingbirds as well as gain knowledge in the fields of biomechanics and ornithology. , Graduate Student

Qualifications: Required: a sincere interest in hummingbirds, a detail-oriented mind, punctuality, and patience. Desired: experience in using MATLAB programming language and completion of an introductory biology course. I may request your curriculum vitae or transcript by email. A short statement about why you are interested in this project is highly encouraged.

Weekly Hours: to be negotiated

Related website: