Avian visual perception: Interocular and intraocular transfer and head-bobbing behaviour in birds A Dissertation submitted for the Degree of “Philosphiae doctoris” (PhD) in Neuroscience at the International Graduate School of Neuroscience (IGSN) of the RUHR-UNIVERSITY BOCHUM by Laura Jiménez Ortega October 2005 Printed with permission of the International Graduate School of Neuroscience of the RUHR-UNIVERSITY BOCHUM First Referee: Prof. Dr. Nikolaus F. Troje Second Referee: Prof. Dr. Onur Güntürkün Third Referee: Prof. Dr. L. Huber (Wien) Date of the oral examination: 30-11-2005 Table of contents 1. GENERAL INTRODUCTION....................................................................................1 1.2 Intraocular and interocular transfer in pigeons ............................................................................................... 2 1.2.1 Intraocular transfer of information ......................................................................................................... 3 1.2.2 Interocular transfer of information.......................................................................................................... 5 1.2.3 Interim summary ....................................................................................................................................... 9 1.3 Visual asymmetries in birds.............................................................................................................................. 10 1.3.1 Right eye/left hemisphere dominances................................................................................................... 11 1.3.2 Left eye/right hemisphere dominances .................................................................................................. 12 1.3.3 Asymmetric interhemispheric transfer.................................................................................................. 14 1.3.4 Interim summary ..................................................................................................................................... 16 1.4 Head-bobbing in birds ...................................................................................................................................... 16 1.4.1 Biomechanical function ........................................................................................................................... 17 1.4.2 Image stabilization................................................................................................................................... 18 1.4.3 Motion parallax........................................................................................................................................ 19 1.4.4 Head-bobbing birds ................................................................................................................................. 20 1.4.5 Interim summary ..................................................................................................................................... 22 1.5 Anatomical substrate........................................................................................................................................ 22 1.5.1 The avian eye............................................................................................................................................ 22 1.5.2 Visual pathways in the avian brain ........................................................................................................ 26 1.5.3 Interim summary ..................................................................................................................................... 30 1.6 Goals of this work............................................................................................................................................. 31 2. GENERAL METHODS ...........................................................................................32 2.1 Experimental arena .......................................................................................................................................... 32 2.2 Motion capture system...................................................................................................................................... 33 2.3 Subjects ............................................................................................................................................................. 34 2.4 Training Procedure .......................................................................................................................................... 34 3. EXPERIMENT 1, 2 AND 3: INTRAOCULAR AND INTEROCULAR TRANSFER IN PIGEONS. ..................................................................................................................38 3.1 Experiment 1: Limits of intraocular transfer in pigeons I: frontal to lateral direction. ................................ 38 3.1.1 Methods .................................................................................................................................................... 39 3.1.2 Results....................................................................................................................................................... 41 3.1.3 Discussion ................................................................................................................................................. 46 3.2 Are pigeons capable of interocular transfer between the two yellow fields? .................................................. 49 3.2.1 Methods .................................................................................................................................................... 50 ii 3.2.2 Results....................................................................................................................................................... 51 3.2.3 Discussion ................................................................................................................................................. 53 3.3 Limits of intraocular transfer in pigeons II: lateral to frontal direction. ....................................................... 56 3.3.1 Methods .................................................................................................................................................... 56 3.3.2 Results....................................................................................................................................................... 57 3.3.3 Discussion ................................................................................................................................................. 59 3.4 Interim summary............................................................................................................................................. 62 4. EXPERIMENT 4: PATTERN RECOGNITION DURING HEAD-BOBBING: ARE PIGEONS CAPABLE OF PATTERN RECOGNITION DURING THE THRUST PHASE? .....................................................................................................................63 4.1 Methods............................................................................................................................................................. 63 4.2 Results............................................................................................................................................................... 67 4.2.1 Percentage of correct responses.............................................................................................................. 67 4.2.2 Head-bobbing motion.............................................................................................................................. 69 4.3.3 Interim summary ..................................................................................................................................... 81 5. EXPERIMENT 5: WHY DO BIRDS BOB THEIR HEADS? ....................................82 5.1 Methods............................................................................................................................................................. 83 5.1.1 List of head-bobbing and non head-bobbing birds............................................................................... 83 5.1.2 Taxonomic tree of head-bobbing and non head-bobbing birds........................................................... 85 5.1.3 Analysis of behavioural and ecological factors under head-bobbing .................................................. 87 5.2 Results............................................................................................................................................................... 89 5.2.1 Head-bobbing and non head-bobbing birds list.................................................................................... 89 5.3 Discussion....................................................................................................................................................... 100 5.3.1 List of head-bobbing and non-bobbing birds: exceptions within a family........................................ 101 5.3.2 Rare or occasional head-bobbing behaviour ....................................................................................... 103 5.3.3 Are body-bobbing birds head-bobbing birds? .................................................................................... 106 5.3.4 Are other-head-movements functions similar to head-bobbing functions?...................................... 106 5.3.5 Head-bobbing evolution