DOI: 10.5061/dryad.hhmgqnks3
title: Ecological and demographic drivers of kin-directed cooperation in a social bird: Insights from a long-term study

description: The evolution of sociality is one of the major evolutionary transitions in
 the history of life and a key step in this transition is the occurrence of
 kin associations. Yet, the question of what demographic processes and
 environmental factors generate kin-structured populations and drive
 kin-directed cooperation remains open. In this review, we synthesize 30
 years of studies of the long-tailed tit Aegithalos caudatus,
 which has a kin-selected cooperative breeding system with redirected help:
 failed breeders may help to raise offspring of conspecifics, typically
 relatives, breeding nearby. We describe the use of ecological,
 demographic, genetic and behavioural approaches to reveal: (a) how
 kin-structured populations (here ‘kin neighbourhoods’) arise; (b) why the
 prevalence of cooperation varies among populations and individuals; and
 (c) how variation in dispersal and opportunities for cooperation influence
 individual fitness. The kin neighbourhoods of long-tailed tits arise from
 three processes. First, natal dispersal is limited and sex-biased so many
 individuals, especially males, recruit as breeders close to their natal
 site. Second, neither dispersal nor migration necessarily disrupts kin
 associations because long-tailed tits often move with close relatives.
 Third, a small effective population size driven by high nest predation
 rates enhances within-population relatedness. Together, these processes
 set the scene for kin-directed helping behaviour by causing spatial
 clustering of relatives. The prevalence of cooperation within kin
 neighbourhoods depends on several factors, both at the population-level
 (annual nest predation rate and length of the breeding season) and
 individual-level (relatedness, familiarity, sex and condition). However,
 limited information on prior social association and the reliability of kin
 discrimination cues hampers our current understanding of individual
 helping decisions.  Finally, variation in dispersal within and
 between sexes affects the probability of interacting with kin, the
 likelihood of cooperation, and accrual of the direct and indirect
 components of inclusive fitness. We use this comprehensive understanding
 of the factors driving cooperative behaviour in long-tailed tits to
 highlight gaps in knowledge and suggest future avenues for research in
 this system, and to make general inferences about the role of dispersal,
 demography and kinship in social evolution.
description: This data originates from the long-term monitoring of a wild
 population of long-tailed tit in the Rivelin Valley (UK). Most individuals
 were captured and colour-ringed, and every breeding attempt was closely
 monitored since 1994, allowing detailed data on local dispersal and
 recruitment rates across breeding seasons. We refer the reader to the
 publication for the method on actual data collection in the field. In
 short, the identity of each breeder was possible, at the vincinity of
 their nest, thanks to the unique colour ring combination their bare on
 their legs. Nestlings were also ringed with unique combinations of
 colour-rings. That allowed us to detect local recruits and estimate the
 proportion of fledglings that recruited locally, for each year (first
 table), and the dispersal distance they performed (distance between their
 natal nest in year Y and their first ever breeding nest in year
 Y+1).    
description: # Ecological and demographic drivers of kin-directed cooperation in a
 social bird: Insights from a long-term study
 [https://doi.org/10.5061/dryad.hhmgqnks3](https://doi.org/10.5061/dryad.hhmgqnks3) ## Description of the data and file structure This data originates from the long-term monitoring of a wild population of long-tailed tit in the Rivelin Valley (UK). Most individuals were captured and colour-ringed, and every breeding attempt was closely monitored since 1994, allowing detailed data on local dispersal and recruitment rates across breeding seasons. These two specific types of data (dispersal distance and recruitment rate) contribute to the knowledge of the species biology and we used and present them in our Review on the drivers of cooperation in the long-term studied population of long-tailed tits. ### Files and variables #### File: Morinay\_et\_al\_2025\_JAE\_recruitment\_rate.csv **Description:** Annual recruitment rate of locally ringed nestlings ##### Variables * Year: Year when the considered nestlings fledged * recruited: number of fledglings which were found breeding in the local population in subsequent years * n: total number of fledglings in Year Y * prop.rec: recruited divided by n * n_broods: total number of broods from which the total number of fledglings n originated from. * recruited.f: number of FEMALE fledglings which were found breeding in the local population in subsequent years * n.f: total number of FEMALE fledglings in Year * prop.rec.f: recruited.f divided by n.f * n_broods.f: total number of broods from which the total number of FEMALE fledglings n originated from. * recruited.m: number of MALE fledglings which were found breeding in the local population in subsequent years * n.m: total number of MALE fledglings in Year * prop.rec.m: recruited.m divided by n.m * n_broods.m: total number of broods from which the total number of MALE fledglings n originated from. #### File: Morinay\_et\_al\_2025\_JAE\_dispersal\_distances.csv **Description:** Natal dispersal distance performed by locally recruited nestlings. ##### Variables * cohort: Year when the considered recruits fledged * metal_ring: unique code on the metal ring of the bird (unique identifier) - From the BTO, UK. * sex: M for male, F for female * lat_natc: latitude of the natal site of the bird. Coordinate Reference System: EPSG:4326. * lon_natc: longitude of the natal site of the bird. Coordinate Reference System: EPSG:4326. * lat_brc: latitude of the first breeding site of the bird, in Year "cohort + 1". Coordinate Reference System: EPSG:4326. * lon_brc: longitude of the first breeding site of the bird, in Year "cohort + 1". Coordinate Reference System: EPSG:4326. * dist: distance (in meters) between the natal site and first breeding site which locations are provided in other columns.  This distance ('great-circle-distance' or 'as the crow flies') was calculated using the distHaversine R function from the geosphere R package. NA: N ot applicable ## Code/software Data format is .csv, which can be opened in a text software as well as R free software, using the function read.csv(file, header = TRUE, sep = ",", dec = ".").