Data and code from: Density and kinship interactively affect natal dispersal in a social bird
Data files
Mar 31, 2026 version files 59.69 KB
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Analysis_of_influencing_factors_on_natal_dispersal.csv
13.80 KB
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Main_analyses.R
43.03 KB
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README.md
2.86 KB
Abstract
Dispersal in animals is influenced by diverse environmental cues, among which population density and kinship are key drivers. High density can promote dispersal by intensifying intraspecific competition or inhibit it through group-living advantages. Likewise, kin interaction may enhance dispersal via kin competition or limit it through kin-selected fitness gains. However, the interplay between them remains inadequately elucidated. We investigated how density and kinship interacted to influence natal dispersal in silver-throated tits (Aegithalos glaucogularis), a social species showing facultative cooperative breeding during the breeding season and group-living thereafter. We found female-biased natal dispersal, consistent with male-biased helping behaviour. For males, the natal dispersal distance was negatively associated with the number of male siblings fledging from the same nest, and this relationship intensified with increasing fledgling density around the natal nest, indicating that density can modulate kin selection’s constraining effect on dispersal. Furthermore, with increasing male sibling number, fledgling density’s effect on male dispersal distance shifted from positive to negative, suggesting that potential kin selection opportunity can reverse the direction of the density effect. These findings demonstrate that density and kin selection opportunities interact to shape dispersal dynamics, offering new insights into their combined roles in driving the evolution of dispersal strategies.
Dataset DOI: 10.5061/dryad.6t1g1jxcp
Description of the data and file structure
Files and variables
File: Main_analyses.R
Description: The main code
File: Analysis_of_influencing_factors_on_natal_dispersal.csv
Description: The main data
Variables
- BirdID: Bird identity
- Natal_nestID: Natal nest identity
- Year: Birth year
- Natal_dispersal_distance: Natal dispersal distance, Response variable (meters)
- Sex: Individual sex (m/f)
- Fledgling_brood_size: Number of fledglings from natal nest
- Male_sibling_number: Number of male siblings that fledged from the same nest
- Local_adult_density: Number of breeding adults around the natal nest within 300 m radius
- Local_fledgling_density: Number of fledglings around the natal nest within 300 m radius
- Cooperative_breeding: Whether the natal nest was cooperative breeding (0 = non-cooperative; 1 = cooperative)
- Hatching_date: number of days from the hatching date relative to 31 December of the previous year
- Hatching_date (real): Specific hatching date
- Reference_date: 1st January of the current year
- Excluded_reason: Whether data was used ("Remained" = usable, others (Fledged from other nests; Nests at the edges might have unmonitored nests within the 300 m radius outside the study area; Nests predated shortly before fledging, some chicks might have survived; Missing variable data) = unusable)
- Kin_nearby: Number of nesting relatives (including parents and male siblings) within 300m radius of the second-year breeding nest
- Male_sibling_nearby: Number of nesting male siblings that fledged from the same nest within 300m radius of the second-year breeding nest
- Parent_nearby: Number of relatives (including male siblings that fledged from the same nest and parents in the social pedigree) around the next-year breeding nest within 300 m radius (0/1/2)
Notes
- The value "na" in data: Data are missing due to reasons documented in the Excluded_reason column (e.g., fledged from other nests; edge nests with potential unmonitored nests outside the 300 m radius; nests predated shortly before fledging with possible chick survival; missing variable data). No reasonable imputation is possible; therefore, "na" is used. Samples containing these values are excluded from related analyses.
Code/software
We used one R script (Main analyses.R) to analyse our data in R 4.4.3
The R script includes:
- Data reading and preprocessing
- Sexual differences in natal dispersal distance analysis
- Interactive effects of density and kin interactions on male natal dispersal
- Effect of natal dispersal distance on the presence of kin
- Visualisation of all statistical results