DOI: 10.5061/dryad.p8cz8wb1t
title: Data from: Unusual sperm morphology in two sedentary songbird species

description: These data describe the morphology of bird sperm cells. The primary
 species are white-breasted nuthatch (Sitta carolinensis) and wrentit
 (Chamaea fasciata), for which we provide data from light microscopy and
 scanning electron microscopy (SEM). We additionally provide SEM data for
 Eurasian and Azores bullfinches (Pyrrhula pyrrhula and P.
 murina). For reproducibility, we provide summarised data on
 ecological and life history traits. We use that data in phylogenetic
 analyses to understand the evolution of the unusual sperm shape that is
 the focus of the paper.  
description: # Data from: Unusual sperm morphology in two sedentary songbird species
 [https://doi.org/10.5061/dryad.p8cz8wb1t](https://doi.org/10.5061/dryad.p8cz8wb1t) ## Description of the data and file structure Our original data are descriptive statistics of sperm morphology from individual male songbirds. Background data on captures are also provided.  For reproducibility, we also include summaries of otherwise-available data. Because of changing species concepts and names, it may not be straightforward to reproduce our results from the original sources. For purposes other than reproducibility, please go to the original source data.  ### Files and variables #### File: NuthatchWrentitData.xlsx **Description:** Morphological measurements of sperm cells from light microscopy and scanning electron microscopy (SEM), with field data. ##### Variables: Most variable names are fully self-contained, including units. * Sperm measurements collected via light microscopy: Head, µm; Midpiece, µm; Flagellum, µm; Total sperm length, µm; SD of total sperm length; CVwm (the coefficient of variation of sperm length, calculated within the sampled cells for the male) * Sperm measurements collected via SEM follow Cramer et al. (2022, DOI: 10.1002/jmor.21524) or Støstad et al. (2019, [https://doi.org/10.1111/evo.13555](https://doi.org/10.1111/evo.13555)). They are Flagellum diameter, µm; N cells' flagellum diameter measured; Acrosome centreline length, µm (ACL); Acrosome volume, µm3 (ACV); Acrosome diameter, µm (AD); Acrosome straight length, µm (ASL); Head length, µm (HL); Membrane width, µm (HMW); Head volume, µm3 (HV); Nucleus centreline length, µm (NCL); Nucleus diameter, µm (ND); Nucleus straight length, µm (NSL); Nucleus volume, µm3 (NV); Waviness (WAV) * A link to the specimen page in database of the University of California, Berkeley's Museum of Vertebrate Zoology is also provided (Arctos link). #### File: CovariatesSpeciesEcology_Dryad.csv **Description:** Provides a description of whether sperm have a "typical" body form or a tadpole-like shape, for all species examined at the Natural History Muesum of the University of Oslo.  ##### Variables: * SpermForm: categorical, "Typical" or "Tadpole" * birdtree_name: the name of the species as found in birdtree.org #### File: DataForPhylo_many_dryad.csv **Description:** Family-level summaries of several life history traits.  ##### Variables: * TaxFam: Taxonomic family according to the IOC taxonomy * label: species name of the representative species from the family, in birdtree.org format * species: species name of the representative species from the family, in birdtree.org format * meanEPP: average level of extra-pair paternity, sourced mainly from Brouwer & Griffith (2019).  * EPPknown: indicates whether extra-pair paternity has been measured (known) or not (unknown). Rows with "unknown" should be removed before analysis * SpermForm: "grey" indicates that only typical-shaped sperm have been observed in this family. "black" indicates that at least one species in this family has tadpole-shaped sperm. * MeanRTM: average relative testes mass (combined testes mass/body mass) across the taxonomic family. Data from Calhim & Birkhead (2006), Calhim & Montgomerie (2015), and Rowe *et al.* (2015). White-throated dipper removed from the averages.  * PropWithCare: Proportion of species with male investment greater than 0 in either the nest building or incubation categories of parental investment in Gonzalez-Voyer et al. (2022) * MeanMigDist: average migration distance (in 1000 km) from Lifjeld et al. (2019). This reflects the straight-line distance from their study population to the center of the winter distribution, with partial migrants and Afrotropical species were assigned 0 value under the assumption that migration distance averages less than 500 km. * PropLongTerm: proportion of species with a long-term pair bond (category 3 in Tobias et al. 2016). #### File: StillerTreeTrimmed.new **Description:** Trimmed version of the phylogeny (newick format) from Stiller et al. (2024) with one representative species per taxonomic family. To be used with file DataForPhylo_many_dryad.csv. #### File: SpTreeSummary.nexus **Description:** Our species-level phylogeny (nexus format) representing the summary of 1000 stage 2, Ericson backbone trees from birdtree.org. To be used with CovariatesSpeciesEcology_Dryad.csv. ## Code/software Excel and NuthatchCode_dryad.R. The latter provides an example analysis for examining the correlation between an ecological variable and the presence of at least one tadpole-shaped sperm in the taxonomic family. Note that we ran these analyses on a computing cluster.