Position in the laying order has sex-specific consequences for reproductive success in adult black-headed gulls
Data files
May 10, 2024 version files 25.62 KB
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Breeding_position.csv
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Early_survival.csv
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README.md
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Reproductive_success.csv
Abstract
Mothers who produce multiple offspring within one reproductive attempt often allocate resources differentially; some maternally-derived substances are preferentially allocated to last-produced offspring and others to first-produced offspring. The combined effect of these different allocation regimes on the overall fitness of offspring produced early or late in the sequence is not well understood, partly because production order is often coupled with birth order, making it difficult to separate effects of pre-natal maternal allocation from those of post-natal social environments. In addition, very little is known about the influence of laying order on fitness in later-life. In this study, we used a semi-natural captive colony of black-headed gulls to test whether an offspring’s position in the laying order affected its early life survival and later life reproductive success, independent of its hatching order. Later-laid eggs were less likely to hatch, but among those that did, survival to adulthood was greater than that of first-laid eggs. In adulthood, the laying order of females did not affect their likelihood of breeding in the colony, but male offspring hatched from last-laid eggs were significantly less likely to gain a breeding position than earlier-laid males. In contrast, later-laid female parents hatched lower proportions of their clutches than first-laid females, but hatching success was unrelated to the laying order of male parents. Our results indicate that gull mothers induce complex and sex-specific effects on both the early survival of their offspring and on long-term reproductive success through laying order effects among eggs of the same breeding attempt.
README: Title of Dataset: Position in the laying order has sex-specific consequences for reproductive success in adult black-headed gulls
Dataset contains 3 excel files:
Early survival
BreedPair: unique identifier for breeding pair
ID: unique identifier for individual egg
Year: calendar year of laying
EggLumped: order in the laying sequence of the individual egg. Factor with 4 levels (A-CD)
Hatched: binary coding for whether the egg hatched (1) or not (0)
Survived: binary coding for whether the nestling inside the egg survived (1) or not (0) to independence at one year old
IncludeSurvivalAnalysis: binary coding for whether this egg was included (1) or not (0) in the analysis of survival to 1 year (see article for description of inclusion criteria).Breeding position
Colour rings: unique identifying code for individual
Sex: molecular sex binary (0 = female, 1 = male)
BirthYear: calendar year of hatching
NatalNest: unique identifier for breeding pair that produced the focal individual
Age2021: age of individual in calendar year 2021
EggOrderLumped: order in the laying sequence of the individual egg. Factor with 4 levels (A-CD)
HatchOrder: order of emergence from the egg in the laying sequence
BecameBreeder? Binary coding whether individual did (1) or did not (0) gain a breeding position
AFR: age in years at which individual first reproducedReproductive success
Bird: unique identifying code for individual
Sex: molecular sex binary (0 = female, 1=male)
NatalNest: unique identifier for breeding pair that produced the focal individual
EggOrderLumped: order in the laying sequence of the individual egg. Factor with 4 levels (A-CD)
EggOrderNumeric: same data as EggOrderLumped but coded as numeric between 1 and 4
HatchOrder: order of emergence from the egg in the laying sequence
BreedingYear: calendar year in which information on reproductive success was recorded
Experiment: Binary coding for whether eggs were experimentally removed (1) or not (0) from the pair
CS: clutch size, number of eggs
Nhatch: number of eggs that hatched
Nfledge: number of nestlings that survived to independence
Also included are two R scripts:
- main analyses
- power anayses for non-siginificant results
Description of the data and file structure
Each row in the excel files is an individual data point (either an egg or an individual bird, depending on the analysis). Please see the above description of the files for information about the contents of each file and what each column refers to. All datafiles are related and derive from the same population of animals.
Methods
Data were collected from a captive population of wild-type black-headed gulls between 2012 and 2021. Each year, breeding attempts in the colony were monitored to collect data on egg laying order, hatching success, survival of offspring, and among adults, various reproductive parameters such as breeding status and nesting success. Data pertaining to each individual were collated in excel.
Usage notes
Microsoft excel, R.