DOI: 10.5061/dryad.jq2bvq89p
title: Extensive variation in feather ornaments of Whiskered Auklets in the Aleutian Islands reflects age, sex, condition, and geography

description: Both sexes of Whiskered Auklets (Aethia pygmaea) display the most
 elaborate feather ornaments of any seabird: a slender black forehead
 crest, and 3 bilaterally symmetrical pairs of white facial plumes
 (superorbital, suborbital, and auricular). We studied patterns of ornament
 variation in 796 banded individuals (147 of known sex, 254 of known age
 from 1 to 16 years) during 1992–2009 at Buldir Island (principally), and 3
 other Aleutian Islands (Davidof, Ulak, and Egg) in Alaska, USA. As
 expected for socially selected traits, ornaments were more variable across
 individuals than anatomical traits in size, but with only slightly
 male-biased sexual dimorphism. Body condition index increased from age 1
 to 3 years but changed little thereafter. Even within birds ≥4 years old,
 ornament size was positively related to body condition index. Subadults
 (one-year-olds) had smaller ornaments than adults (age 2–16 years), but
 there was no further change in ornament size as adults aged and no
 evidence of senescence even in the oldest birds (&gt;8 years old).
 Nonetheless, overall ornament size varied from year to year at Buldir and
 was correlated with indices of both ocean climate and auklet productivity
 in the preceding 2–5 years. From Buldir to Egg Island (1,266 km), the size
 of both anatomical and ornamental traits increased by 5–15% except for
 bill depth, which was largest in birds from Buldir and Egg at opposite
 ends of the Aleutian breeding range. This study is one of the few to
 examine patterns of ornament variation in a long-lived, socially
 monogamous bird, even though such patterns are crucial to understanding
 the relationship between sexual selection and life history.
description: Data was collected in the Aleutian Islands, Alaska, mainly on
 Buldir, during the Whiskered Auklet breeding seasons from 1992-2009. Data
 were analyzed in R, and graphs were drawn using R and DataGraph.
description: # Extensive variation in feather ornaments of Whiskered Auklets in the
 Aleutian Islands reflects age, sex, condition, and geography ## GENERAL
 INFORMATION Dryad DOI https://doi.org/10.5061/dryad.jq2bvq89p ### 1. Paper
 Citation Jones IL, Hunter FM, Seneviratne SS, Williams JC, Montgomerie R.
 2022. Extensive variation in feather ornaments of Whiskered Auklets in the
 Aleutian Islands reflects age, sex, condition, and geography.
 *Ornithology* 139:ukab082. doi:10.1093/ornithology/ukab082 ### 2.
 Originators Robert Montgomerie ### 3. Contact information Dept. Biology,
 Queen’s University, Kingston, ON K7L 3N6, Canada. email:
 [mont@queensu.ca](mailto:mont@queensu.ca) ### 4. Date of data collection
 1992-2008 ### 5. Geographic locations of data collection Aleutian Islands,
 Alaska, USA: Buldir Island (principally), plus Davidof, Ulak, and Egg) ###
 6. Information about funding sources that supported the collection and
 curation of the data Discovery Grants from the Natural Sciences and
 Engineering Research Council of Canada (NSERCC; RGPIN/182591-2012 to
 I.L.J. and RGPIN/05711-2014 to R.M.); two research grants from the
 National Geographic Society Committee for Research and Exploration (to
 I.L.J. and F.H.M.); and postdoctoral fellowship support from an NSERCC to
 I.L.J. and the Natural Environment Research Council (UK) to F.H.M. ##
 ACCESS INFORMATION ### 1. Licenses/restrictions placed on the data
 Creative Commons Zero (CC0) as required by Dryad While attribution is not
 legally required under CC0, Dryad and the authors strongly recommend
 citing the data source as a scholarly courtesy, as follows: Jones, I. L.,
 F. M. Hunter, S. S. Seneviratne, J. C. Williams, and R. Montgomerie
 (2021). Data from: Extensive variation in feather ornaments of Whiskered
 Auklets in the Aleutian Islands reflects age, sex, condition, and
 geography. Ornithology 139:ukab082.
 [https://doi.org/10.5061/dryad.jq2bvq89p](https://doi.org/10.5061/dryad.jq2bvq89p) ### 2. Data derived from other sources Ocean climate data from the following sources (see data file 2 below for more detailed information on the source of each variable): * Pacific Decadal Oscillation index: the average of monthly values (Mantua et al. 1997, Mantua and Hare 2002) for August-April preceding auklet resighting periods (May-June) ([[http://jisao.washington.edu/pdo/PDO.latest](http://jisao.washington.edu/pdo/PDO.latest)] * Aleutian Low Pressure index: average intensity for December through March (Beamish et al. 1997) preceding auklet resighting periods ([[http://www.pac.dfo-mpo.gc.ca/sci/sa-mfpd/climate/clm_indx_alpi.htm](http://www.pac.dfo-mpo.gc.ca/sci/sa-mfpd/climate/clm_indx_alpi.htm)] * North Pacific Index: the average of monthly values (Trenberth and Hurrell 1994) for August-April preceding auklet resighting periods ([[http://www.cgd.ucar.edu/cas/jhurrell/npindex.html](http://www.cgd.ucar.edu/cas/jhurrell/npindex.html)] ## DATA FILES AND VARIABLES Missing data is indicated by empty cells or NA (Not Available) ### 1. DEMOGwhau.csv Demographic data on Whiskered Auklets from Buldir * Year = year * WHAUsurv = annual survival rate of adults (measured by capture-mark-recapture and resighting of marked birds at Buldir; Jones et al. 2002, Jones et al. 2007) * WHAUprod = annual productivity measured as mean number of chicks fledged per pair (from Bond et al. 2011) * WHAUhd = mean hatch day of the year ### 2. OceanClimate.csv Indices of ocean climate from 1992-2008 * PDOp12mths = Pacific Decadal Oscillation (preceding May-April mean) From: [https://climatedataguide.ucar.edu/climate-data/pacific-decadal-oscillation-pdo-definition-and-indices](https://climatedataguide.ucar.edu/climate-data/pacific-decadal-oscillation-pdo-definition-and-indices) * PDOaugapril = Pacific Decadal Oscillation (preceding November-March mean) From: [https://climatedataguide.ucar.edu/climate-data/pacific-decadal-oscillation-pdo-definition-and-indices](https://climatedataguide.ucar.edu/climate-data/pacific-decadal-oscillation-pdo-definition-and-indices) * ALPInew = Aleutian Low Pressure Index (preceding year) From: [[https://open.canada.ca/data/en/dataset/4bb821ce-bef7-46d3-95d2-064065f1bda4](https://open.canada.ca/data/en/dataset/4bb821ce-bef7-46d3-95d2-064065f1bda4)] See Surry and King (2015) * NPIp12mths = North Pacific Index (preceding May-April mean) From: [[https://climatedataguide.ucar.edu/climate-data/north-pacific-np-index-trenberth-and-hurrell-monthly-and-winter](https://climatedataguide.ucar.edu/climate-data/north-pacific-np-index-trenberth-and-hurrell-monthly-and-winter)] See also: Hurrell, James &, Phillips, Adam & National Center for Atmospheric Research Staff (Eds). Last modified 2025-05-02 "The Climate Data Guide: North Pacific (NP) Index by Trenberth and Hurrell; monthly and winter.” Retrieved from [https://climatedataguide.ucar.edu/climate-data/north-pacific-np-index-trenberth-and-hurrell-monthly-and-winter](https://climatedataguide.ucar.edu/climate-data/north-pacific-np-index-trenberth-and-hurrell-monthly-and-winter) on 2025-07-08. * NPIndjfm = North Pacific Index (preceding November-March mean) From: [[https://climatedataguide.ucar.edu/climate-data/north-pacific-np-index-trenberth-and-hurrell-monthly-and-winter](https://climatedataguide.ucar.edu/climate-data/north-pacific-np-index-trenberth-and-hurrell-monthly-and-winter)] * SLPbasedNAMI = SLP based NAMI index (preceding December-March) From: [[https://climatedataguide.ucar.edu/climate-data/hurrell-wintertime-slp-based-northern-annular-mode-nam-index](https://climatedataguide.ucar.edu/climate-data/hurrell-wintertime-slp-based-northern-annular-mode-nam-index)] See also: Phillips, Adam & National Center for Atmospheric Research Staff (Eds). Last modified 2025-05-02 "The Climate Data Guide: Hurrell wintertime SLP-based Northern Annular Mode (NAM) Index.” Retrieved from [https://climatedataguide.ucar.edu/climate-data/hurrell-wintertime-slp-based-northern-annular-mode-nam-index](https://climatedataguide.ucar.edu/climate-data/hurrell-wintertime-slp-based-northern-annular-mode-nam-index) on 2025-07-08. * mvENSOp12mths = El Nino Southern Oscillation Index (preceding May-April mean) From: [https://www.psl.noaa.gov/enso/mei ](https://www.psl.noaa.gov/enso/mei)*Data/image provided by the NOAA Physical Sciences Laboratory, Boulder, Colorado, USA, from their website at [https://psl.noaa.gov/](https://psl.noaa.gov/).* * ENSOindexp12mths = El Nino Southern Oscillation Index (May-April mean) From: [[http://www.cpc.ncep.noaa.gov/data/indices/oni.ascii.txt](http://www.cpc.ncep.noaa.gov/data/indices/oni.ascii.txt)] ### 3. WHAUmeas.csv The main dataset from birds measured in the field * Year = year * Month = month * Day = day * DOY = day of the year * BandNo = band number * Rby = status (status of the individual captured: n = newly banded bird (first capture), Rwi = retrap of a bird previously captured as an n in the same year, Rby = recapture of a bird banded in a previous year, RwiRby = retrap of a bird previously captured as an Rby in the same year, rm = remeasurement of the bird on the same day * Measurer = person who took the measurements (ILJ = Ian L. Jones, FHM = Fiona M. Hunter, SS = Sampath S. Seneviratne, HJM = Hannah J. Munro) * ageCAT = age category (ad = adult (&gt;1 year old), sub = subadult (1 year old) * age = age in years * sex = sex (m = male, f = female, NA = unknown); determined by molecular sexing method * sex2 = sex (m = male, f = female, u = unknown); determined by molecular sexing method * mass = body mass (± 1 g) * tarsus = tarsus length (±0.1 mm; measured from the notch at the proximal end of the tarsometatarsus to the distal end of the tarsometatarsus on the underside of the foot) * wing = wing length (±0.1 mm) * billDepth = bill depth (±0.1 mm; measured along a line passing mid-way through the nostril from the edge of the feathering at the base of the culmen to the lowest point on the gonys) * culmen = culmen length (±0.1 mm; measured from the edge of the feathering at the base of the bill to the bill tip) * crest = crest length (±0.1 mm) * AuricularLeft = left side auricular plume length (±0.1 mm) * AuricularRight = right side auricular plume length (±0.1 mm) * max2Aur = maximum of the two sides for auricular plume length (±0.1 mm) for birds with plumes on both sides * mean2Aur = mean of the two sides for auricular plume length (±0.1 mm) for birds with plumes on both sides * SuperLeft = left side superorbital plume length (±0.1 mm) * SuperRight = right side superorbital plume length (±0.1 mm) * max2Super = maximum of the two sides for superorbital plume length (±0.1 mm) for birds with plumes on both sides * mean2Super = mean of the two sides for superorbital plume length (±0.1 mm) for birds with plumes on both sides * SubLeft = left side suborbital plume length (±0.1 mm) * SubRight = right side suborbital plume length (±0.1 mm) * max2Sub = maximum of the two sides for suborbital plume length (±0.1 mm) for birds with plumes on both sides * mean2Sub = minimum of the two sides for suborbital plume length (±0.1 mm) * Web = foot web damage score (0 = no damage, 1 = minor damage like a small hole in one web, 2 = major damage or ‘tears’ or complete absence of a web on at least one foot) * BroodPatch = index of the size of the brood patch (0 = no brood patch, 1.0 = full brood patch; e.g., 0.9 indicates a bird with brood patch defeathering estimated to be about 90% of a full brood patch * Breeder = evidence that the bird was breeding (1) or non-breeding (0) at the time of capture. If the bird had a fully vascularized brood patch, or one beginning to refeather, or if it had a chick meal in its throat pouch, it was scored as a breeder. If the bird did not have a brood patch, it was scored as a non-breeder. ### 4. WHAUrepeatability.csv Data for birds measured more than once during this study; data and variables same as in WHAUmeas except for the addition of * SameDay = indicates whether repeated measures were taken on the same day (y = yes, n = no) * Same14d = indicates whether repeated measures were taken on the 14-d period (y = yes, n = no) ### 5. WHAUall4islands.csv Data from four Aleutian islands; variables same as in WHAUmeas except for * Site = island * band = band number ## CODE SCRIPTS AND WORKFLOW ### 1. Rwhiskauklets.Rmd This is an R notebook with all of the analyses included in the paper, the Supplementary Material and Statistical Supplement. ## SOFTWARE VERSIONS R version 4.1.2 (2021-11-01) with the following loaded packages * ‘lme4’ package version: 1.1.27.1 * ‘MuMIn’ package version: 1.43.17 * ‘lmerTest’ package version: 3.1.3 * ‘tidyverse’ package version: 1.3.1 * ‘emmeans’ package version: 1.6.3 * ‘sjPlot’ package version: 2.8.9 * ‘sjstats’ package version: 0.18.1 * ‘car’ package version: 3.0.11 * ‘psych’ package version: 2.1.6 * ‘rsq’ package version: 2.2 * ‘MASS’ package version: 7.3.54 * ‘easystats’ package version: 0.4.3 * ‘rptR’ package version: 0.9.22 * ‘visreg’ package version: 2.7.0 * ‘smatr’ package version: 3.4.8 * ‘DescTools’ package version: 0.99.43 * ‘caret’ package version: 6.0.88 * ‘rmcorr’ package version: 0.4.4 * ‘lavaan’ package version: 0.6.9 * ‘ggforce’ package version: 0.3.3 ## ADDITIONAL FILES ### 1. StatisticalSupplement.pdf Tables of statistical output to support analyses presented in the paper ## REFERENCES Beamish, R.J. & McFarlane, Gordon & Noakes, David & Folkes, M. & Ivanov, V., & Kurashov, V. 1997. A comparison of the Aleutian Low Pressure Index and the Atmospheric Circulation Index as indices of Pacific salmon abundance trends. North Pacific Anadromous Fish Commission Doc. 289. 24p. Department of Fisheries and Oceans, Pacific Biological Station, Nanaimo, B.C. Canada. V9R 5K6.doi: 10.13140/RG.2.2.35441.48485. Bond, A.L., Jones, I.L., Sydeman, W.J., Major H.L., Minobe, S., Williams, J.C., and G.V. Byrd. 2011. Reproductive success of planktivorous seabirds in the North Pacific is related to ocean climate on decadal scales. Marine Ecology Progress Series 424: 205-218. Jones, I.L., F.M. Hunter and G.J. Robertson. 2002. Annual adult survival of Least Auklets (Aves, Alcidae) varies with large-scale climatic conditions of the North Pacific Ocean. Oecologia 133: 38-44. Jones, I.L., F.M. Hunter, G.J. Robertson, J.C. Williams, and G.V. Byrd. 2007. Covariation among demographic and climate parameters in Whiskered Auklets (Aethia pygmaea). Journal of Avian Biology 38: 450-461. Mantua, N. J., S. R. Hare, Y. Zhang, J. M. Wallace, and R. C. Francis 1997. A Pacific Interdecadal Climate Oscillation with Impacts on Salmon Production. Bull. Amer. Meteor. Soc., 78, 1069–1080, [https://doi.org/10.1175/1520-0477(1997)078](https://doi.org/10.1175/1520-0477\\\(1997\\\)078)&lt;1069:APICOW&gt;2.0.CO;2. Mantua, N.J., and S.R.Hare. 2002. The Pacific Decadal Oscillation. Journal of Oceanography 58, 35–44. [https://doi.org/10.1023/A:1015820616384](https://doi.org/10.1023/A:1015820616384) Trenberth, K.E. and J.W. Hurrell. 1994. Decadal atmosphere-ocean variations in the Pacific. Climate Dynamics 9: 303–319. [https://doi.org/10.1007/BF00204745](https://doi.org/10.1007/BF00204745) Surry, A.M., and King, J.R. 2015. A new method for calculating ALPI: The Aleutian Low Pressure Index. Can. Tech. Rep. Fish. Aquat. Sci. 3135: v + 31 p. Trenberth, K.E. and J.W. Hurrell. 1994. Decadal atmosphere-ocean variations in the Pacific. Climate Dynamics 9: 303–319. [https://doi.org/10.1007/BF00204745](https://doi.org/10.1007/BF00204745)