Research

Haverflock

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We are studying collective animal behavior and predator-prey interactions with an emphasis on understanding how birds integrate sensory perceptions, cognition and flight. Projects include:

• Falcon pursuit strategies: working with an international team of over a dozen participating falconers, we are studying how falcons, hawks and other raptors find, track and capture their prey. Our methods combine the use of tiny animal-borne cameras worn by the birds that record their environment with ground-based video and computer models that let us interpret
• How raptors search their environment visually during foraging for prey and during prey pursuits: experimental characterization and theoretical modeling of the statistics of raptor saccadic head motion
• Flocking and calling: how do flocks of chimney swifts and cliff swallows use calling to form flocks and to regulate flock dynamics?
• A study of a phenomenon called mobbing, whereby smaller prey animals (in our case, barn swallows and terns) harass and attack a predator—here, a raptor such as the sharp-shinned or Cooper’s hawks that can prey upon local birds. We have used particle-tracking methods and statistical analyses to understand and model the dynamical rules governing this behavior.

Participants

• Suzanne Amador Kane, Physics Department, Haverford College
• Andrew ("Harvey") Fulton (Physics and Biophysics '14) flocking and calling in chimney swifts and cliff swallows
• Elliott Schwartz (Physics '14) stereometric video of dense flocks of cliff swallows
• Lee Rosenthal (Physics '15) flocking and calling in chimney swifts and cliff swallows
• Marjon Zamani (Physics and Biophysics '13) experiments and analysis of raptor saccadic head motions, flocking and calling by chimney swifts and falcon pursuit strategies. Coauthored our Haverflock ImageJ tracking userguide.
• Alyssa Mayo (Physics '13) experiments and analysis of chimney swift flocking and calling, rock pigeon flocking in aviaries and collision avoidance by black-headed gulls.
• Eleanor Tecosky-Feldman (research intern) experiments and analysis of chimney swift flocking and calling
• Emma Oxford (Physics '13) co-wrote our Raven Pro supplementary userguide and helped develop our bird-mounted GPS and other sensors.
• Marjon Zamani (Physics '13) co-wrote our local ImageJ tracking userguide and performed experiments on using video and bioacoustic methods in summer 2011
• Anna Schall (Physics '12) worked during fall '09 to analyze online videos of crows mobbing various predators
• Emily Cunningham (Physics '12) wrote our simulation code and took tern mobbing data in summer 2009.
• M. Elias Tousley (Haverford Physics '11) worked on this project since its inception; his senior thesis project involved taking the swallow-raptor and tern mobbing data, writing code, doing data analysis and helping create our experimental setup.
• Owen Glaze (a '09 graduate of Lower Merion High School) performed research in summer 2009 before attending Penn State's main campus in the fall. Owen wrote much of the image analysis code and took the swallow-raptor data with Elias.

Previous Projects

A Biophysical Model of Prokaryotic Diversity in Geothermal Hot Springs

Physics majors Anna Klales '09 (Harvard PhD program), Jim Duncan ’03 (Oregon State Geosciences PhD program) and Liz Janus Nett'04 (U. Wisconsin PhD program)

Photosynthetic bacteria living in geothermal hot spring environments have surprisingly complex ecosystems with an unexpected level of genetic diversity.  In particular, their thermal gradients support genetically distinct bacterial strains that differ in their preferred temperatures for reproduction and photosynthesis.  Each region along the thermal gradient exhibits multiple strains of photosynthetic bacteria adapted to several distinct thermal optima, rather than the expected single thermal strain adapted to the local environmental temperature.  Here we analyze microbiology data from several ecological studies to show that the thermal distribution field data exhibit several universal features independent of location and specific bacterial strain.  These include the distribution of optimal temperatures of different thermal strains and the functional dependence of the net population density on temperature.  We present a simple population dynamics model of these systems that explains the observed diversity of different strains of the photosynthetic bacteria, the observed thermal population distributions and certain features of population dynamics observed in laboratory studies of the same organisms.

Anna Klales, James Duncan, Elizabeth Janus Nett, and Suzanne Amador Kane, “Biophysical model of prokaryotic diversity in geothermal hot springs”, Phys. Rev. E 85(2) 021911 (2012)