IAP-26-120

Manipulation without hands: the causes and consequences of avian vertebral evolution

The ability to manipulate objects has played a crucial role in human evolution. Using hands, we have invented tools and built shelters, which enabled us to expand even to extreme environments on Earth. This ability is not, however, restricted to primates and their hands. Many animals manipulate objects like food and nest material, and very little is known about the evolutionary causes and consequences of this dexterity.

In particular, manipulation of objects is almost ubiquitous amongst birds. Most birds manipulate material to build some sort of nest for raising offspring, and many species manipulate their food to extract edible fruits from skins and to remove inedible feathers from captured prey. During such manipulation, while the beak directly grips an object, it is the neck that enables precise placement of that beak. This is in contrast to primates, where the primary manipulators (hands and arms) are separate from the head. The avian neck therefore not only supports the brain and key sensory organs, but also facilitates dexterity, with important consequences for breeding and foraging performance.

There is a substantial degree of variation in avian neck morphology. For example, known cervical counts (the number of vertebrate that form the neck), one of the simplest measures of neck structure, range from 10 to 26, in contrast to the uniform seven found across mammals. The causes and consequences of this considerable variation remain largely unknown. In part, this is due to the lack of data – the largest study to date on avian neck morphology contained only ~120 species, and even less is known about the inter- and intra-specific variation in the role of the neck in manipulation tasks.

This project combines a global-scale analysis of avian neck evolution and a fine-scale analysis of dexterous behaviour in a model species, zebra finches. The student will build a comprehensive data set on avian neck structure by capitalizing on the world’s largest collection of avian skeletal specimens in the Natural History Museum (Tring). They will then combine this information with recently-published behavioural databases to test whether these morphological differences are associated with specific nesting or foraging ecology. Finally, the student will carry out behavioural experiments with live birds to examine how much variation in dexterity performance exists within the same neck morphology. This project will help us better understand whether it is the physical structure of manipulator, the neck morphology, or the way the manipulator is used, the bird’s behaviour, that determines dexterity. The outcome of this project is likely to provide novel design inspiration for non-humanoid robotic manipulators.

The successful candidate will learn how to design and conduct behavioural experiments, as well as statistical analysis and data handling in R, Python, or another coding language. The project will suit a student with a strong interest in behavioural ecology, macroecology and evolutionary biology.

As the three supervisors’ expertise covers all aspects of this project, training will be provided in all relevant techniques, including handling and measuring specimens, experimental design, behavioural analysis and phylogenetic comparative modelling.

The student will also gain highly transferrable skills such as analytical thinking, data analysis, scientific writing, scientific communication, in an intellectually supportive environment, with opportunities for disseminating their findings at national and international conferences.

Establish measurement protocols in Newcastle, with visits to Natural History Museum Tring for data collection and to Aberdeen for phylogenetic comparative modelling training in year 1. Phylogenetic comparative modelling and write up in Newcastle in year 2. Behavioural experiments with zebra finches in St Andrews, data analysis and write up in Newcastle in year 3.

Year 1

Training in specimen measurements. Establish measurement protocols. Visits to NHM Tring to collect neck morphology data. Training in phylogenetic comparative analysis using machine learning tools (with Dr Catherine Sheard, Aberdeen). Training in bird handling and experimental design.
Milestone: Developed measurement protocols and complete global dataset on avian neck morphology.

Year 2

Analyse neck morphology data using phylogenetic comparative models, assessing the link between neck morphology and foraging or nesting traits. Milestones: Complete analyses for first two thesis chapters. The student will present findings at an ECR-targeted conference (e.g. ASAB Easter meeting).

Year 3

Run behavioural experiments testing factors affecting dexterity performance within the same neck structure (with Prof Sue Healy, St Andrews). Analyse video data using deep-learning models, and identify behavioural motifs unique to and shared between individuals. Statistical analyses will quantify the relationships between behavioural motifs, individual characteristics and dexterity performance. Milestone: Complete analyses for the third thesis chapter; first manuscript submitted.

Year 3.5

Final statistical analyses, thesis writing, and submission. Milestones: The student will present findings at an international conference. Thesis submitted; at least one additional manuscript ready for submission.

Training in experimental design, collecting behavioural data, data analysis, writing papers, presenting data in lab groups, and presenting at national and international conferences. Will also provide the opportunity to develop knowledge in behavioural ecology and macro ecology, neuroscience and biomechanics.