DOI: 10.5061/dryad.95x69p8wc
title: Does brain size matter? Linking cognitive and ecological traits to climate change vulnerability in seabirds

description: Understanding the mechanisms that increase a species resilience to climate
 change is central to predicting how they are likely to respond. One
 determinant of vulnerability to climate change identified in multiple taxa
 is the thermal range of a species’ distribution. In this context, species
 with narrow thermal ranges are reportedly more vulnerable to climate
 change. One paradigm for predicting the range of environmental conditions
 that a species can occupy is the ‘cognitive buffer hypothesis’. The
 cognitive buffer hypothesis predicts that species with larger brain sizes
 (relative to body mass) display greater behavioural flexibility and are
 more able to persist and thrive within variable environmental conditions.
 Following the theory, we expected that species with larger relative brain
 sizes will occupy broader thermal ranges and be less vulnerable to climate
 change. In this study, we collate species-specific information for 206
 species of seabird. We then use Phylogenetic Generalised Least Squares
 (PGLS) regression and path analysis to quantify and identify linkages
 connecting relative brain size, thermal range, migration pattern,
 hand-wing index, foraging behaviour, vulnerability to climate change and
 extinction risk while controlling for shared ancestry between species. We
 focused our study on seabirds, a highly threatened group that displays
 large variation in these variables. Previous work has also proposed that
 seabird species with a wider thermal range across their geographic
 distribution are more likely to be impacted by climate change. Consistent
 with the cognitive buffer hypothesis, we found that seabird thermal range
 increases with relative brain size. We also found that having a larger
 relative brain size or being a long-distance migrant may indirectly reduce
 extinction risk through a species’ thermal range. Additionally, we found
 that having a higher hand-wing index and employing generalist foraging
 behaviours reduces seabird vulnerability to climate change and extinction
 risk. Our study suggests that having a larger relative brain
 size, being a long-distance migrant, employing generalist foraging
 behaviour and having a higher hand-wing index can lower extinction risk.
 Identifying the ecological traits that promote species resilience is
 crucial for determining which species are most at risk of population
 declines and directing species conservation.
description: # Does brain size matter? Linking cognitive and ecological traits to
 climate change vulnerability in seabirds #### Does brain size matter?
 Linking cognitive and ecological traits to climate change vulnerability in
 seabirds
 [https://doi.org/10.5061/dryad.95x69p8wc](https://doi.org/10.5061/dryad.95x69p8wc) ## Description of the data and file structure This dataset contains data and code crucial for understanding the key findings of our research paper: 'Does brain size matter? Linking cognitive and ecological traits to climate change vulnerability in seabirds'. **Authors** Junghyuk Keum (1), Ferran Sayol (2), Florian Orgeret (3) and Catharine Horswill (4). 1. Centre for Biodiversity and Environmental Research, Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6B, UK 2. Centre for Ecological Research and Forestry Applications (CREAF), Cerdanyola del Vallès, 08193, Spain 3. Marine Apex Predator Research Unit, Department of Zoology, Institute for Coastal and Marine Research, Nelson Mandela University, Gqeberha 6031, South Africa 4. Centre for Biodiversity and Environmental Research, Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6B, UK; Institute of Zoology, Zoological Society of London, Regent’s Park, London, NW1 4RY, UK **Overview** The uploaded files include the dataset, phylogenetic tree and R-script to comprehend and run all the analyses practiced on our paper. Information contained in each file is detailed below.  ### Files and variables #### File: Bird brain measurement\_Keum et al. 2025.xlsx **Description:** Records for the brain size measurement of 48 newly measured seabird species. Measurement was done using specimens from the Natural history museum at Tring.  In February 2022.  ##### Variables * Code: Specimen code. * Species(birdsoftheworld): Species nomenclature based on birds of the world. * Species(jetz): Species nomenclature based on Jetz et al. (2012). * family: Species family. * order: Species order. * sex: Specimen sex (f= female, m=male, u=unknown). * weight microbaloon: Total weight (g) of micro baloons used to fill the brain cavity of the specimen. * volume ml: Specimen brain size estimate (ml) calculated using the measured weight and known density of the microbaloon. * Species avg.: Averaged brain size (ml) for each species. * Locality: Location where the specimen was collected.  #### File: Keum\_et\_al\_2025\_seabird\_data.csv **Description:** This dataset is comprised of 10 columns describing species-specific ecological traits of 206 seabird species examined in our study. Explanations for each column are described in below section. ##### Variables * Species: Species nomenclature. * Migration: Species migration pattern (1=migrant, 0=resident). * Brain: Brain size (ml) (Detailed sources on the original paper). * Body: Body mass (g) (Detailed sources on the original paper). * ref.brain: Reference for brain size data (Detailed sources on the original paper). * ref.body: Reference for body mass data (Detailed sources on the original paper). * Foraging: Forging niche as 4 categories based on descriptions from Birds of the World database. * IUCN_cat: Extinction risk of seabird species based on IUCN redlist catagories. (CR=Critically Endangered, LC= Least Concern, VU= Vulnerable, NT= Near Threatened, EN= Endangered) * Climate_vul: species vulnerability to (being harmed by) climate change impact (1=vulnerable, 0=not vulnerable). * Thermal_range: SST range (℃) of seabird species habitat excluding migratory passage.  #### File: Keum\_et\_al\_2025\_seabird\_code.R **Description:** This file contains the R code required to regenerate the analyses within our manuscript. Specific instructions and details are described within the code script. #### File: BirdTree\_Ericson\_MCC.tre **Description:** This file contains the phylogenetic tree data for all seabird species of interest. Opening and processing the file can be made possible using the attached R file.  ## Code/software ### Data Formats * **R Files**: * **.R**: Contains the R code required to regenerate the analyses presented on our manuscript. * **Csv Files:** * **.csv**: It contains the list of seabird species included in the study and the associated morphological and ecological traits. * **Phylogenetic Tree Files:** * **.tre**: Includes phylogenetic tree data for the species of interest. You may open and process the file using the attached R code. - **Excel Files**: * **.xlsx**: Contains the brain size measurement records. ### Recommended Software for Data Analysis: #### Data Analysis: * **Primary Software**: R  * **Secondary Software**: RStudio -An open-source platform that can handle various R codes and data formats with ease. #### Excel Data Analysis: * **.xlm Files**: Microsoft Excel - For handling Excel macro files.