https://doi.org/10.5061/dryad.:

Description of the data and file structure

The data and accompanying .R scripts were used to test whether having experience as a helper affected a number of different breeding and fitness related parameters in the Seychelles warbler (Acrocephalus sechellensis) in the paper "The impact of helping experience on helper life-history and fitness in a cooperatively breeding bird." Specifically, they were used to test whether helping experience had an effect on:

• Whether or not an individual acquired a dominant breeding position (binary response variable: yes/no)
• The age at which an individual acquired a dominant breeding position (if ever; continuous response variable)
• The length of an individual's dominant breeding tenure (if dominance was acquired; continuous response variable)
• The number of genetic offspring produced after an individual first acquired dominance (i.e., the "skills" hypothesis; continuous response variable)
• An individual's lifetime reproductive success (continuous response variable)
• An individual's lifespan (ad-hoc analysis; continuous response variable)

From this, it was found that helping experience alone has no effect on any of the breeding or fitness-related parameters above, except that individuals with helping experience started breeding at an older age and dominant females with prior helping experience had longer lifespans than individuals that did not have helping experience. In addition, females with co-breeding experience produced more offspring after acquiring a dominant breeding position and had a higher lifetime reproductive success than females without co-breeding experience.

For all datasets, empty cells correspond to an N/A value.

natalInfo.xlsx

Data collected during the natal field period of the focal bird, providing information on their natal environment. These data were used to determine variables such as whether or not the focal bird had a helper, the identity of their social father, variables relating to their genetic mother and social father (e.g., age when the focal individual hatched). Genetic parents with a p-value of <0.8 were also removed from the dataset during data preparation in experiencePrep.R. Information about the natal territory was also collected so that it could be combined with data from an additional dataset (territoryQuality.xlsx) to determine the natal territory quality. Description of variable, data-type, and descriptions for the abbreviations of categorical data are provided.

• BirdID: The unique ID of the focal bird (numerical).
• HelpingLRS_07_SexEstimate: The sex of the focal bird, determined using molecular sexing techniques (numerical; 0: female; 1: male; converted to categorical in experiencePrep.R).
• BirthDate: Hatch dates are estimated from nest watches based on observed lay dates, hatch dates, or fledge dates. If this information is not available, hatch date may also be estimated by considering the physiological features of the focal bird e.g., eye colour (date).
• MumID: The unique ID of the genetic mother of the focal bird, determined using the genetic pedigree (numerical).
• MumBirthDate: The estimated hatch date of the genetic mother of the focal bird (date).
• DadID: The unique ID of the genetic father of the focal bird, determined using the genetic pedigree (numerical).
• DadBirthDate: The esimated hatch date of the genetic father of the focal bird (date).
• p: The p value indicating the confidence of the relationship between the focal bird and the assigned genetic mother and father (continuous).
• FieldPeriodID: The unique ID of the field period in which the focal bird hatched (numerical).
• NatalTerritoryNumber: The unique territory number in which the focal bird hatched (numerical).
• TerritoryID: The unique territory ID in which the focal bird hatched (numerical).
• BreedGroupID: The specific group of birds that reside within the breeding group during the field period in which the focal bird hatched (numerical).
• GroupMembers: The unique IDs of all birds existing within the breeding group when the focal bird hatched (numerical).
• sys_SexEstimates_SexEstimate: The estimated sex of each group member within the breeding group in which the focal bird hatched (numerical; 0: female; 1: male; converted to categorical in experiencePrep.R).
• GroupMembersStatus: The breeding status of each group member within a breeding group during the field period in which the focal bird hatched. (categorical; EGG: egg; CH: chick; FL: fledgling; OFL: old fledgling; H: helper; AB: additional bird (non-helper); ABX: not enough information to determine helper status; B: budder (taking over another territory); NSA: not seen within that particular field period, but seen in a subsequent field period; BrF: dominant, breeding female; BrM: dominant, breeding male; TBRF: breeding female that was translocated to a different island; TBRM: breeding male that was translocated to a different island; SBR: subordinate breeder (however, co-breeding females were recalculated within the experiencePrep.R dataset); U: unknown status).
• GroupMembersBirthDate: The estimated hatch date of each group member within the breeding group in which the focal bird hatched (date).

statusInfo.xlsx

The following data were collected over a focal individual’s lifetime, to gain insight into the breeding statuses that they held within different territories at different points in time. These data were used, primarily, to determine whether they been a helper (males and females) or co-breeder (females only) before acquiring dominance or at any point throughout their lifetime. Description of variable, data-type, and descriptions for the abbreviations of categorical data are provided.

• BirdID: The unique ID of the focal bird (numerical).
• BirthDate: Hatch dates are estimated from nest watches based on observed lay dates, hatch dates, or fledge dates. If this information is not available, hatch date may also be estimated by considering physiological features of birds when they are first caught e.g., eye colour (date).
• BreedGroupID: Corresponds to the specific group of birds that resided within a territory during a specific field period in which the focal bird was alive (numerical).
• TerritoryID: The unique territory number in which the focal bird was assigned a breeding status (numerical).
• Status: The breeding status that the focal bird held within each unique breeding group (categorical; EGG: egg; CH: chick; FL: fledgling; OFL: old fledgling; H: helper; AB: additional, sexually mature bird (non-helper); ABX: not enough information to determine helper status of additional bird; B: budder (individual taking over another territory); NS: not seen in this field period; NSA: not seen within this particular field period, but seen in a subsequent field period so known to be alive; BrF: dominant breeding female; BrM: dominant breeding male; TBRF: breeding female that was translocated to a different island; TBRM: breeding male that was translocated to a different island; SBR: subordinate breeder (however, co-breeding females were recalculated within the experiencePrep.R dataset); U: unknown status; SEEN1: seen once within this territory; SEEN2: seen twice within this territory: FLOAT: non-territorial individual with no permanent breeding status within the territory).
• FieldPeriodID: The field period in which the focal individual held a breeding status within the particular breeding group (numerical).
• PeriodStart: The date at which the field period started (date).
• PeriodEnd: The date at which the field period ended (date).

lastSeen.xlsx

These data were used to determine the lifespan of each focal bird (supplementary model 2), as well as exclude birds that were believed to be alive at at the end of the sampling period in 2018 (as their fitness metrics have the capacity to still change). To determine lifespan, the last date for each of these variables was taken (or the midpoint of last field period in which they had a breeding status assigned, if catch/seen data are not available). Description of variable, data-type, and descriptions for the abbreviations of categorical data are provided.

• BirdID: The unique ID of the focal bird (numerical).
• LastCaught: The date when the focal bird was last caught in the mist-net (date).
• LastSeen: The date when the focal bird was last observed in the field (date).
• ChickCollection: The date when the focal bird was captured in the nest as a chick (if ever; date).
• EggCollection: The date when the focal bird was captured in the nest as an egg (if ever; date).

summerIndex.xlsx

These data were used to estimate territory quality when datapoints were missing for particular field seasons. The summer index was used to determine whether the field period was in the summer or winter, and then then the mean of the previous and following field period of the same season-type were used to estimate territory quality for the field period with the missing datapoint. Field periods with a summerIndex of ≥0.5 were classed as summer seasons, whereas field periods with a summer index of <0.5 were considered winter seasons. Description of variable, data-type, and descriptions for the abbreviations of categorical data are provided.

• TerritoryID: Each unique territory ID present within a particular field period (numerical).
• FieldPeriodID: The unique field period ID corresponding to to the data in PeriodStart/PeriodEnd/SummerIndex (numerical).
• PeriodStart: The date at which the field period started (date).
• PeriodEnd: The date at which the field period ended (date).
• SummerIndex: The summer index corresponding to the field period, with ≥0.5 indicating a summer field period (numerical).

territoryQuality.xlsx

These data were used to allow territory quality to be used as a variable in the necessary models. From this, the natal territory quality could be calculated for each focal bird, as well as the mean territory qualities for the field periods prior to dominance, during their dominance tenures, and over their lifetimes. These data were also used in conjunction with the data from the summerIndex datasheet, which allowed for missing territory quality data to be estimated. Description of variable, data-type, and descriptions for the abbreviations of categorical data are provided.

• Island: The island where the data was collected, used to subset data to only include data from Cousin Island. Description of variable, data-type, and descriptions for the abbreviations of categorical data are provided (categorical; CN: Cousin; CE: Cousine; DN: Denis; FR: Fregate).
• Year: The year that the territory quality data was collected (continuous).
• TerritoryID: The unique territory number corresponding to the value in TQcorrected (numerical).
• FieldPeriodID: The unique field period ID (numerical).
• TQcorrected: The territory quality data for the corresponding territory within the given field period. TQcorrected is determined by considering the arthropod abundance within the particular territory (continuous). <br>

Code/Software

All statistical analyses were performed in RStudio (4.2.1) using the datasets described above.

experiencePrep.R

Within this script, all of the datasets above were imported and used to calculate the variables used in the models within experienceAnalyses.R. The variables used within the models (and the type of data i.e., factor, continuous) include:

• Whether the focal individual helped at any point prior to dominance, or during their lifetime (factor: yes/no).
• Whether the focal individual co-bred at any point prior to dominance, or during their lifetime (females only; factor: yes/no).
• The age of their genetic mother when the focal individual was born (both as linear and quadratic variables; continuous).
• The natal territory quality of the focal individual (continuous).
• The mean territory quality of all of the territories that the focal individual inhabited prior to acquiring dominance (continuous).
• The mean territory quality of all of the territories in which the focal individual was a dominant breeder (continuous).
• The mean territory quality of all of the territories that the focal individual inhabited over the course of their lifetime (continuous).
• Whether or not the focal individual had a helper themselves when they were a nestling/fledgling (factor: yes/no).
• The proportion of breeding seasons that the focal individual had helpers during their dominant breeding tenure (continuous).
• The ID of the focal individual's genetic mother (factor).
• The ID of the focal individual's social father (factor).
• The cohort (year of birth) of the focal individual (continuous). <br>

experienceAnalyses.R

This script was used to run the analyses detailed in 'Description of the data and file structure', as well as generate the corresponding graphs for models with the relevant significant results.