Visual Resolution of Anna's Hummingbirds (Calypte anna) in Space and Time by Tyee Kenneth Fellows B.Sc., The University of British Columbia, 2013 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in The Faculty of Graduate and Postdoctoral Studies (Zoology) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) June 2015 © Tyee Kenneth Fellows, 2015 Abstract The sampling of spatial and temporal visual information for all living organisms is finite. The speed and accuracy of visual systems contributes in part to an animal's sensitivity to visual motion. The ability to see swift motions is a crucial adaptation among bird species, which are high-speed animals that navigate in a three-dimensional world. Hummingbirds are emerging as important models for studying visual guidance in vertebrates. However, their sensitivity to visual motion remains unknown. A method that can be used to identify hummingbirds' sensitivity to visual motion is to characterise the spatial and temporal acuity of their visual system. It is hypothesised that temporal acuity scales positively with mass-specific metabolic rate and negatively with body size, and spatial acuity scales positively with body size. Given hummingbirds possess the highest mass- specific metabolic rates among vertebrates and the smallest body sizes among birds, I predicted that the Anna's hummingbird (Calypte anna) would have high temporal and low spatial acuities among bird species. Using operant conditioning and optocollic reflex experiments, I identified the temporal and spatial acuity thresholds of the Anna's hummingbird's visual system. Training hummingbirds to differentiate flickering from non-flickering lights at different rates and colours measured their temporal acuity for wavelengths of light between 380-750nm. Spatial acuity was measured by subjecting hummingbirds to rotating stimuli that varied in spatial frequency and luminance. The results indicate the hummingbird's temporal acuity is between 70 and 80Hz, and is unaffected by light colour (red, white, and ultraviolet). Spatial resolving capacity is measured to be between 4.95 and 6.18 cycles per degree in light conditions below 1.77 candela/m2. Therefore, my measurements of spatial acuity in the Anna's hummingbird provide support for a positive relationship with body size, and my measurements of temporal acuity do not provide support for a positive relationship with mass-specific metabolic rate. This study marks the first time both spatial and temporal acuity is measured in a sustained hovering animal. ii Preface This thesis is an original intellectual product of the author, Tyee Fellows. All experimental procedures were approved by the UBC Animal Care Committee (certificate number: A10-0233) and conducted in accordance with guidelines followed by the Canadian Council on Animal Care. The experimental design and writing of this thesis was done myself with guidance from Dr. Douglas Altshuler. The illustration of the avian eye was adapted by Michela Sutter from the Manual of Ornithology: Avian Structure and Function (Proctor and Lynch, 1998). The experimental arena for measuring temporal acuity was designed and constructed myself. The arena for measuring spatial acuity was designed myself, but built by Bruce Gillespie and Vince Grant of the Zoology Mechanical Workshop. Ambient light measurements for both experimental arenas were collected using a Minolta LS- 100 photometer, which was kindly provided by Dr. Deborah Giaschi and used by Kim Meier. Alexandra Ferland and Ricardo Pelai digitised the videos from the spatial acuity experiment. Statistical analysis for the spatial and temporal acuity dataset was done with assistance from Dr. Rosalyn Dakin. Specifically, she assisted in creating the scripts to perform the Dunnett's contrast test for the spatial acuity data and bootstrapping the confidence intervals in the temporal acuity dataset. All software programs using Arduino, MATLAB, PostScript, Python, and R languages were written myself, with the exception of two: fmf2lift and DLTdv5. The video recording for the spatial acuity experiments were converted from fmf to avi files using a Python script written by Paolo Segre called fmf2lift. The software used to track head position during the spatial acuity experiments used a MATLAB program called DLTdv5, written by Ty Hedrick (Hedrick, 2008). The equation used to estimate hummingbird temporal acuity in the concluding chapter was provided by Kevin Healy himself (Healy et al., 2013). iii Table of Contents Abstract ......................................................................................................................................... ii Preface .......................................................................................................................................... iii Table of Contents ........................................................................................................................ iv List of Tables ............................................................................................................................... vi List of Figures ............................................................................................................................. vii List of Equations ......................................................................................................................... ix List of Abbreviations .................................................................................................................... x Acknowledgements ...................................................................................................................... xi Dedication ................................................................................................................................... xii 1 Introduction ............................................................................................................................. 1 2 Research Chapter .................................................................................................................. 20 2.1 Introduction ................................................................................................................... 20 2.2 Materials & Methods .................................................................................................... 21 2.2.1 Birds ....................................................................................................................... 21 2.2.2 Temporal Acuity Arena ........................................................................................ 21 2.2.3 Temporal Acuity Training ................................................................................... 25 2.2.4 Temporal Acuity Experiment .............................................................................. 26 2.2.5 Spatial Acuity Arena ............................................................................................. 28 2.2.6 Spatial Acuity Experiment ................................................................................... 30 iv 2.2.7 Data Analysis ......................................................................................................... 32 2.2.7.1 Temporal Acuity ............................................................................................ 32 2.2.7.2 Spatial Acuity ................................................................................................ 33 2.3 Results ............................................................................................................................ 36 2.3.1 Temporal Acuity .................................................................................................... 36 2.3.2 Spatial Acuity ........................................................................................................ 38 2.4 Discussion ....................................................................................................................... 45 3 Conclusion .............................................................................................................................. 49 Bibliography ............................................................................................................................... 58 Appendices .................................................................................................................................. 77 Appendix A: Controlling LED Flicker Rates in Arduino ................................................. 77 Appendix B: Randomising Temporal Experiments in R ................................................... 82 Appendix C: Programming in PostScript ........................................................................... 83 Appendix D: Randomise Spatial Acuity Experiments in R .............................................. 92 Appendix E: Statistical Analysis of Temporal Acuity Data in R ...................................... 93 Appendix F: Processing Spatial Acuity Data in MATLAB ............................................. 101 Appendix G: Statistical Analysis of Spatial Data in R ..................................................... 112 Appendix H: Dunnetts Contrast for Assessing Spatial Acuity in R ............................... 115 Appendix I: Pupil Diameter Analysis in R ....................................................................... 118 v List of Tables Table 1. Dunnet contrasts for assessing hummingbird spatial acuity ................................... 44 Table 2. The scope