Measuring avian bill size: Comparing and evaluating 3D surface scanning with traditional size estimates in Australian birds

Unidimensional measurements for estimating bill size, like length and width, are commonly used in ecology and evolution, but can be criticised due to issues with repeatability and accuracy. Furthermore, formula-based estimates of bill surface area tend to assume uniform bill shapes across species, which is rarely the case. 3D surface scanning can potentially help overcome some such issues by collecting detailed external morphology and direct measurements of surface area, rather than composite estimates of size. Here, we evaluate the use of 3D surface scanners on avian museum specimens to test the repeatability of 3D-based measurements and compare these to traditional formula-based methods of estimating bill size from unidimensional measurements. Using 28 Australian bird species, we investigate inter-observer repeatability of surface area measurements from 3D surface scans. We then compare 3D-based size estimates to formula-based size estimates to infer the accuracy and precision of form..., , , # Measuring avian bill size: comparing and evaluating 3D surface scanning with traditional size estimates [https://doi.org/10.5061/dryad.sxksn038q](https://doi.org/10.5061/dryad.sxksn038q) We investigated measurement repeatability between observers for bill surface area, as derived from 3D scans. We applied 3D surface scans on a diverse set of birds, and further collected unidimensional measurements. We assess how these unidimensional measurements can be used in different formulae to estimate bill surface area. ## Description of the data and file structure The dataset contains bill surface area measurements, extracted from two observers using 3D surface scans of diverse bird species (columns billSA_measurer1 and 2). It also contains unidimensional measurements (bill length, width, depth, width between the nares, and upper and lower bill profile length; as titled in columns), measured using calipers (or, in the case of total bill width and the profile length, derived from the 3D scan...在生态学与进化生物学领域，喙部尺寸（bill size）估算常采用长度、宽度等单维度测量（unidimensional measurements）手段，但这类方法因重复性与精准性方面的缺陷常受诟病。 此外，基于公式的喙表面积（bill surface area）估算通常假设不同物种间喙部形态均一，而实际情况极少如此。三维表面扫描（3D surface scanning）技术可通过采集精细的外部形态数据并直接测量表面积，而非基于复合尺寸估算，从而有望解决上述部分问题。 本研究针对鸟类馆藏标本（avian museum specimens）开展三维表面扫描，旨在评估基于三维扫描的测量方法的重复性，并将其与传统的基于单维度测量的公式化喙部尺寸估算方法进行对比。我们以28种澳大利亚鸟类为研究对象，探究基于三维表面扫描的表面积测量的观察者间重复性（inter-observer repeatability）。进而基于三维尺寸估算与公式化尺寸估算的对比，推断[原文未完成]。# 鸟类喙部尺寸测定：对比评估三维表面扫描技术与传统尺寸估算方法 https://doi.org/10.5061/dryad.sxksn038q 本研究针对三维扫描获取的喙表面积测量值，探究观察者间的测量重复性。我们对多样化鸟类类群开展三维表面扫描，并同步采集单维度测量数据，进而评估这些单维度测量值可通过何种不同公式实现喙表面积的估算。 数据集与文件结构说明 本数据集包含由两位观察者基于多样化鸟类三维表面扫描获取的喙表面积测量值（对应列名为billSA_measurer1与billSA_measurer2），同时包含单维度测量数据：喙长、喙宽、喙深、鼻孔（nares）间宽度，以及上下喙轮廓长度（对应列名即为上述名称）。其中部分数据采用游标卡尺（calipers）测量（喙总宽度与轮廓长度则由三维扫描数据衍生得到，原文此处未完成）。