Burns Sara M, Bonier Frances
Department of Biology, Queen's University, Kingston, ON, Canada.
PeerJ. 2020 Sep 22;8:e10037. doi: 10.7717/peerj.10037. eCollection 2020.
Many biological studies require the capture of individuals for sampling, for example for measurement of morphological or physiological traits, or for marking individuals for later observations. Capture methods employed often vary both within and between studies, and these differing methods could be more or less effective in capture of different individuals based on their morphology or behavior. If individuals that are prone to capture by the selected method differ with respect to traits of interest, such sampling bias could generate misleading or simply inaccurate results. The selection of capture methods could introduce two different forms of sampling bias, with the individuals that are sampled differing from the population at large or with individuals sampled via one method differing from individuals that could be sampled using a different method. We investigated this latter form of sampling bias by comparing individual birds sampled using two common capture techniques. We caught free-ranging black-capped chickadees () using walk-in traps baited with seed and mist nets paired with playback of an audio stimulus (conspecific mobbing calls). We measured 18 traits that we expect might vary among birds that are trappable by these differing methods-one that targets birds that are food motivated and potentially less neophobic and another that targets birds that respond readily to a perceived predation risk. We found no differences in the sex, morphology, initial and stress-induced corticosterone concentrations, behavioral response to a novel object, or behavioral response to a predator between individuals captured by these two methods. Individual variation in the behavioral response to a novel object was greater among birds caught by mist nets, suggesting this method might provide a sample that better reflects population-level individual variation. We do not know if the birds caught by these two methods provide a representative sample of the population at large, but can conclude that selection of either of these two common capture methods can similarly sample mean trait values of a population of interest. To accurately assess individual variation, particularly in behavior, mist nets might be preferable.
许多生物学研究需要捕获个体进行采样，例如测量形态或生理特征，或标记个体以便后续观察。研究中采用的捕获方法往往在研究内部和研究之间都有所不同，而且这些不同的方法基于个体的形态或行为，在捕获不同个体时可能或多或少会更有效。如果容易被所选方法捕获的个体在感兴趣的特征方面存在差异，这种采样偏差可能会产生误导性或仅仅是不准确的结果。捕获方法的选择可能会引入两种不同形式的采样偏差，即所采样的个体与总体不同，或者通过一种方法采样的个体与使用不同方法可能采样到的个体不同。我们通过比较使用两种常见捕获技术采样的个体鸟类，研究了后一种形式的采样偏差。我们使用装有种子的步入式诱捕器和与音频刺激（同种鸟鸣叫声）回放配对的雾网，捕获了自由放养的黑顶山雀（）。我们测量了18种我们预计可能在可被这些不同方法捕获的鸟类之间有所不同的特征——一种针对受食物驱使且可能较少新物恐惧的鸟类，另一种针对对感知到的捕食风险有快速反应的鸟类。我们发现，通过这两种方法捕获的个体在性别、形态、初始和应激诱导的皮质酮浓度、对新物体的行为反应或对捕食者的行为反应方面没有差异。在被雾网捕获的鸟类中，对新物体的行为反应的个体差异更大，这表明这种方法可能提供一个能更好反映种群水平个体差异的样本。我们不知道通过这两种方法捕获的鸟类是否能代表整个种群，但可以得出结论，选择这两种常见捕获方法中的任何一种，都可以类似地采样感兴趣种群的平均特征值。为了准确评估个体差异，特别是行为方面的差异，雾网可能更可取。
