Object manipulation without hands: kinematics and evolution of nest building by birds

手艺是人类行为的一个标志。几百万年来，双手使人类能够开发出重要的创新，包括工具、即使在极端环境中的庇护所，以及可以将我们带到地球上任何地方和进入太空的交通工具。灵长类的手由五个手指和一个具有详细关节和肌肉结构的手掌组成，这使得灵活的操作动作成为可能。然而，令人惊讶的是，有些建筑是由动物建造的，与人类的手工艺惊人地相似，比如鱼钩、编织结和陶器，但它们是不用手建造的。这种结构的建造者是鸟类：比如乌鸦处理叉状树枝来制作钩状工具来提取食物，编织鸟用草带打结来筑巢，或者燕子和燕子用泥巴来制作锅状的巢。这些鸟是如何在没有手的情况下，仅仅用它们的嘴就做出这样的人类结构的？回答这个基本问题不仅将为这种非凡的手工艺能力的进化起源提供重要的科学见解，而且还可以为工业机器人和为受损或缺失的手设计医疗假肢提供灵感和见解。为了研究鸟类如何用手搭建结构，我将使用先进的跟踪、实验室和野外实验，并结合比较分析来研究鸟类筑巢行为的细节。筑巢是物体操纵的一个极好的模型：大多数鸟类都会筑巢；筑巢可以用各种各样的材料建造，包括植物、动物和人造物体。我的方法由两个互补的方法组成：行为实验，以确定鸟类在处理巢材料时所使用的详细动作，以及一个大规模计算模型，以调查喙形状和巢材料是否一起进化。为了研究各种动物的身体形状和筑巢材料特征之间的相互作用，我将使用三种鸟类：白眉麻雀编织者、斑马雀和谷仓燕子，因为这些物种具有不同的喙形状，使用不同类型的筑巢材料。为了确定鸟类在筑巢过程中如何移动它们的喙，我将通过与我的东道主苏珊·希利教授及其合作者埃克塞特大学的安迪·杨博士和SOKENDAI的长谷川博士进行国际合作，在英国、南非和日本进行行为实验。为了从行为实验的视频片段中获取和分析鸟类运动的信息，我将开发自动跟踪软件，并与爱丁堡大学的芭芭拉·韦伯教授合作，使用机器学习来分析数据。通过实验和分析，我将能够告诉鸟类使用什么技术来处理不同的巢材料，以及当一种材料改变其物理性质时，这些技术是如何变化的。在项目的后半部分，我将构建一个全球模型，在达勒姆大学的萨利·斯特里特博士和圣安德鲁斯大学的凯文·拉兰德教授和凯瑟琳·谢尔德博士的监督下，研究各种鸟类的喙形状是否随着筑巢材料的进化而进化。使用这两种方法(行为实验和进化建模)，范围从精细到全球，我将确定比尔操纵物体的优势和局限性，最终提供对人类双手真正独特特征的见解。

Crafting is a hallmark of human behaviour. For millions of years, hands have enabled humans to develop important innovations, including tools, shelter even in the extreme environments, and vehicles that can carry us anywhere on Earth and into space. Primate hands consist of five digits and a palm with detailed joints and muscle structure, which enable flexible manipulative actions. Amazingly, however, there are structures built by animals that are uncannily similar to human craftwork, such as fishhooks, woven knots and pottery, but that are built without hands. The builders of such structures are birds: such as crows processing a forked branch to make a hooked tool for extracting food, weaverbirds making knots from grass strips to make a nest, or swallows and ovenbirds using mud to make pot-like nests. How do these birds make such human-like structures without hands, simply using their bills? Answering this basic question would provide not only the important scientific insights into the evolutionary origin of this remarkable crafting ability, but could also provide inspirations and insights for the design of industrial robots and medical prosthetics for damaged or missing hands. To examine how birds build structures hands-free, I will use advanced tracking, lab and field experiments, along with comparative analyses to study the details of nest-building behaviour in birds. Nest building is an excellent model for object manipulation: most bird species build nests; and nests can be made from a wide range of materials including plants, animals and artificial objects. My methods consist of two complementary approaches: behavioural experiments to establish detailed motions used by birds while they handle nest material, and a large-scale computational model to investigate if bill shape and nest materials evolved together. To investigate interactions between a broad range of animals' body shape and nest material characteristics, I will use three bird species: white-browed sparrow weavers, zebra finches and barn swallows, as these species have different bill shapes and use different types of nest material. To determine how birds move their bills during nest building, I will carry out behavioural experiments in the UK, South Africa and Japan through my international partnerships with my host PI Prof Susan Healy and Collaborators Dr Andy Young at Univ Exeter, and Dr Masaru Hasegawa at SOKENDAI. To acquire and analyse the information on bird movements from video footage of the behavioural experiment, I will develop automatic tracking software, and analyse the data using machine learning, in collaboration with Prof Barbara Webb at Univ of Edinburgh. From the experiments and analysis, I will be able to tell what techniques birds use to handle different nest materials, and how the techniques change when a material changes its physical properties. In the latter part of the project, I will construct a global model to examine if bill shape evolved with nest material in a wide range of bird species, under the supervision of Collaborator Dr Sally Street at Durham University and Prof Kevin Laland and Dr Catherine Sheard at Univ of St Andrews. Using these two methods (behavioural experiments and evolutionary modelling) ranging from fine- to global-scale, I will identify the advantages and limitations of object manipulations by bills, ultimately providing insights into the truly unique characteristics of human hands.