DOI: 10.5061/dryad.s7h44j15w
title: Age-related reproductive performance of the Adélie Penguin, a long-lived seabird exhibiting similar outcomes regardless of individual life-history strategy

description: 1. Age-related variation in reproductive performance in long-lived
 iteroparous vertebrate species is common, with performance being
 influenced by within-individual processes, such as improvement and
 senescence, in combination with among-individual processes, such as
 selective appearance and disappearance. Few studies of age-related
 reproductive performance have compared the role of these drivers within a
 metapopulation, subject to varying degrees of resource competition. 2. We
 accounted for within- and among-individuals changes among known-aged
 Adélie penguins (Pygoscelis adeliae) during 17 years (1997 to 2013), at
 three clustered colonies of disparate size, to understand patterns in
 age-related reproductive success during early and late adulthood. 3. Age
 at first reproduction (AFR) was lowest, and number of breeding attempts
 highest, at the largest colony. Regardless of AFR, success improved with
 early post-recruitment experience. For both oldest and youngest
 recruitment groups, peak performance occurred at the end of their
 reproductive lifespan indicating a possible cost of reproduction.
 Intermediate recruitment groups reached peak performance in their
 mid-reproductive lifespan and with intermediate breeding experience,
 before decreasing. Breeding success was lowest for the initial breeding
 attempt regardless of AFR, but we observed subsequent variation relative
 to recruitment age. Gaining experience by delaying recruitment positively
 influenced reproductive performance early in the reproductive lifespan,
 and was most evident for the youngest breeders. Oldest recruits had the
 highest initial and peak breeding success. Differences in AFR resulted in
 tradeoffs in reproductive lifespan or timing of senescence but not in the
 overall number of breeding attempts. 4. Patterns differed as a function of
 colony size, and thus competition for resources. Early life improvement in
 performance at the larger colonies was primarily due to within-individual
 factors and at the largest colony, AFR. Regardless of colony size
 late-life performance was positively related to the age at last
 reproduction, indicating selective disappearance of lower performing
 individuals. 5. These results highlight that different life-history
 strategies were equally successful, indicating that individuals can
 overcome potential tradeoffs associated with early- and late-life
 performance. These results have important implications for understanding
 the evolution of life-history strategies responsible for driving
 population change.
description: Data from: "Age-related reproductive performance of the
 Adélie penguin, a long-lived seabird exhibiting similar outcomes
 regardless of individual life-history strategy" PJ Kappes, KM Dugger,
 A Lescroël, DG Ainley, G Ballard, KJ Barton, PO’B Lyver, & PR
 Wilson (2021) Journal of Animal Ecology Data are
 uploaded separately for different analyses. IDs have been
 recoded.  "BreedingSuccess"<br> Data
 for the population-level analysis, used to model age-related variation in
 breeding success for different catagories of age at first reproduction and
 to account for selective dissappearance in late life reproduction (Table
 2; Table 3; Figure 2; Figure 3; Table S1 (Full data set); Table S2; Table
 S3; Table S4; Table S5; Figure S1; Figure S2)  ID     
        Individual identity (recoded)<br> colony      Breeding colony
 (i.e. Bird, Crozier, & Royds)<br> season      Year of
 breeding season always starting with year that birds arrived to breed
 (e.g. arrive October 1999 = 1999)<br> success     1 = chick
 successfully fledged; 0 = nest failed    <br> breeder     1 =
 observed engaging in breeding behavior (i.e., incubating, brooding,
 feeding chick); 0 = not observed in breeding behaviors<br> age     
      True age (in years)<br> afr            Age at first
 reproduction (in years)<br> afrc          Age at first reproduction
 (recoded as 4 level factor); 3 = 3 years; 4 = 4 years; 5 = 5-8 years; 6 =
 9+ years<br> expt         True breeding experience: first breeding
 attempt = 0 and +1 for each subsequent breeding attempt (sabbatical years
 = 0)<br> expl         Learned breeding experience: first breeding
 attempt = 0 and +1 for each year bird is alive after first breeding
 attempt <br> alr            Age at last reproduction (in
 years) "EarlyAdulthoodBirdData"<br>
 Data for the analysis of factors underpinning breeding success in early
 adulthood (controlling for selective appearance)<br> (Table 4a;
 Table S1 (Early adulthood) ID            Individual
 identity (recoded)<br> season     Year of breeding season always
 starting with year that birds arrived to breed (e.g. arrive October 1999 =
 1999)<br> success    1 = chick successfully fledged; 0 = nest
 failed    <br> ysfba       Years since first breeding
 attempt<br> afr           Age at first reproduction (in
 years)<br> ba1          1 = first breeding attempt; 0 = subsequent
 breeding attempts
 "EarlyAdulthoodCrozierData"<br> Data for the
 analysis of factors underpinning breeding success in early adulthood
 (controlling for selective appearance)<br> (Table 4a; Table S1
 (Early adulthood) ID            Individual identity
 (recoded)<br> season     Year of breeding season always starting
 with year that birds arrived to breed (e.g. arrive October 1999 =
 1999)<br> success    1 = chick successfully fledged; 0 = nest
 failed    <br> ysfba       Years since first breeding
 attempt<br> afr            Age at first reproduction (in
 years)<br> ba1          1 = first breeding attempt; 0 = subsequent
 breeding attempts
 "EarlyAdulthoodRoydsData"<br> Data for the
 analysis of factors underpinning breeding success in early adulthood
 (controlling for selective appearance)<br> (Table 4a; Table S1
 (Early adulthood) ID            Individual identity
 (recoded)<br> season     Year of breeding season always starting
 with year that birds arrived to breed (e.g. arrive October 1999 =
 1999)<br> success    1 = chick successfully fledged; 0 = nest
 failed    <br> ysfba       Years since first breeding
 attempt<br> afr           Age at first reproduction (in
 years)<br> ba1         1 = first breeding attempt; 0 = subsequent
 breeding attempts
 "LateAdulthoodBirdData"<br> Data for the analysis
 of factors underpinning breeding success in late adulthood (controlling
 for selective disappearance)<br> (Table 4b; Table S1 (Late
 adulthood) ID           Individual identity
 (recoded)<br> season     Year of breeding season always starting
 with year that birds arrived to breed (e.g. arrive October 1999 =
 1999)<br> success    1 = chick successfully fledged; 0 = nest
 failed    <br> alr           Age at last reproduction (in
 years)<br> ybd         Years before death (in years)<br> lba 
         1 = last breeding attempt; 0 = previous breeding
 attempts "LateAdulthoodCrozierData"<br>
 Data for the analysis of factors underpinning breeding success in late
 adulthood (controlling for selective disappearance)<br> (Table 4b;
 Table S1 (Late adulthood) ID             Individual
 identity (recoded)<br> season      Year of breeding season always
 starting with year that birds arrived to breed (e.g. arrive October 1999 =
 1999)<br> success     1 = chick successfully fledged; 0 = nest
 failed    <br> alr            Age at last reproduction (in
 years)<br> ybd          Years before death (in years)<br> lba 
          1 = last breeding attempt; 0 = previous breeding
 attempts "LateAdulthoodRoydsData"<br>
 Data for the analysis of factors underpinning breeding success in late
 adulthood (controlling for selective disappearance)<br> (Table 4b;
 Table S1 (Late adulthood) ID             Individual
 identity (recoded)<br> season      Year of breeding season always
 starting with year that birds arrived to breed (e.g. arrive October 1999 =
 1999)<br> success     1 = chick successfully fledged; 0 = nest
 failed    <br> alr            Age at last reproduction (in
 years)<br> ybd          Years before death (in years)<br> lba 
          1 = last breeding attempt; 0 = previous breeding
 attempts
description: The attached archived file(s) contain data derived from a long
 term field project monitoring individual Adelie penguins at capes Bird,
 Crozier, and Royds, Ross Island, Antarctica and Beaufort Island,
 Antarctica. This is a request to please let us know if
 you use them.  Several of the co-authors have spent the best part of their
 careers collecting the data. If you plan to analyse the
 data, there are a number of reasons why it would be very helpful if you
 could contact Grant Ballard (gballard@pointblue.org) before doing
 so: 1) Occasionally we discover and correct errors in
 the data. 2) The data are complex and workers who do
 not know the study system are likely to benefit from advice on
 interpretation. 3) At any one time, quite a few people
 within the existing project collaboration are analysing data from this
 project. Someone else may already be conducting the analysis you have in
 mind and it is desirable to prevent duplication of effort.
 4) In order to maintain funding for the project and for further
 analyses, every few years we submit proposals to funding agencies. It is
 therefore very helpful for those running the project to know which data
 analyses are in progress elsewhere. If you are
 interested in analysing the detailed project data in any depth, you may
 find it helpful to have access to the full relational database rather than
 the files available here. If so, we are always open to further
 collaboration. The individual bird identities have been
 recoded and should therefore not be linked with data archived from other
 papers which include penguin data from these breeding colonies or that are
 associated with the Penguin Science (https://penguinscience.com/) research
 project.