Relationship between Channel Island Melospiza melodia (Song Sparrow) bill size and vegetation, seed extraction time, bite force, and climate (2014-2016)

Inferring the environmental selection pressures responsible for phenotypic variation is a challenge in adaptation studies as traits often have multiple functions and are shaped by complex selection regimes. We provide indirect evidence that morphology of the multifunctional avian bill is primarily shaped by climate and thermoregulatory ability in Melospiza melodia (Song Sparrows) on the California Channel Islands. Our research builds on a study in Song Sparrow museum specimens that demonstrated a positive correlation between bill surface area and maximum temperature, suggesting a greater demand for dry heat dissipation in hotter, xeric environments. We sampled contemporary sparrow populations across three climatically distinct islands to test the hypotheses that bill morphology is influenced by habitat differences with functional consequences for foraging efficiency and is related to maximum temperature and, consequently, important for thermoregulation. Measurements of >500 live indi..., Live animals were captured with mistnets, banded, and measured. Bill measurements were converted to conical surface area following Greenberg and Danner (2012). Environmental data was extracted from WorldClim2 using mistnet sampling locations. , Input data files for all analyses in R Markdown: bill_ms_analyses.Rmd
Missing values are removed from all files, and only individuals with complete data are included in analyses. Data are labeled to correspond with Objectives 1-6 listed in R Markdown file., # Channel Island *Melospiza melodia* (Song Sparrow) bill size, vegetation, climate, seed extraction time, and bite force

[https://doi.org/10.5061/dryad.wwpzgmsjc](https://doi.org/10.5061/dryad.wwpzgmsjc)

This dataset contains data from field measurements of Channel Island *Melospiza melodia* (Song Sparrow) bill morphology, vegetation within Song Sparrow habitats, climate associated with Song Sparrow sampling locations, individual seed extraction times, and bite force. Song Sparrows were sampled during the breeding season from 2014-2016 on three California Channel Islands (Santa Cruz Island, San Miguel Island, and Santa Rosa Island). 

Individual measurements of bill morphology and body size were used to determine whether bill metrics are significantly predicted by vegetation and climate. Bill depth and bill shape were used to determine whether bill morphology predicts bite force and/or seed extraction time in wild Song Sparrows. 

## Principal investigator contact information

All dat...

探究驱动表型变异的环境选择压力是适应性研究中的一大难题，因为生物性状往往兼具多重功能，并受复杂选择机制的塑造。本研究针对加州海峡群岛的歌带鹀（*Melospiza melodia*, Song Sparrow）展开，为兼具多重功能的鸟类喙部形态主要受气候与体温调节能力塑造这一观点提供了间接证据。
本研究基于此前一项针对歌带鹀馆藏标本的研究展开，该研究发现喙表面积与最高气温呈正相关，暗示在炎热干旱的环境中，生物对干热散热的需求更高。我们对三座气候特征迥异的岛屿上的歌带鹀当代种群进行了采样，以此验证两项假说：其一，喙部形态受生境差异影响，并对觅食效率产生功能性影响；其二，喙部形态与最高气温相关，因此对体温调节至关重要。
本研究共采集了超500只活体个体的数据：研究人员采用雾网捕获野生歌带鹀，为其佩戴环志脚环并进行形态测量。参照Greenberg与Danner（2012）的方法，将喙部测量数据转换为锥形表面积。环境数据通过雾网采样点从WorldClim2数据库中提取。
本研究所有分析的输入数据文件均为R Markdown格式：bill_ms_analyses.Rmd。所有数据文件均已剔除缺失值，仅保留数据完整的个体用于分析。数据标签与R Markdown文件中列出的1-6号研究目标一一对应。# 加州海峡群岛歌带鹀（*Melospiza melodia*, Song Sparrow）喙部大小、生境植被、气候、种子取食时长与咬合力
[https://doi.org/10.5061/dryad.wwpzgmsjc](https://doi.org/10.5061/dryad.wwpzgmsjc)
本数据集包含加州海峡群岛歌带鹀（*Melospiza melodia*, Song Sparrow）的野外测量数据，具体包括喙部形态、歌带鹀生境内的植被状况、采样点对应的气候数据、个体种子取食时长以及咬合力。研究于2014-2016年的繁殖季，在三座加州海峡群岛（圣克鲁兹岛、圣米格尔岛与圣罗莎岛）上开展歌带鹀采样。
研究人员通过个体的喙部形态与体型测量数据，探究植被与气候是否能显著预测喙部指标。同时利用喙部深度与喙部形状数据，分析野生歌带鹀的喙部形态是否能预测其咬合力与/或种子取食时长。
## 项目负责人联系方式
所有数据...