The genetic structure of animal populations has considerable behavioural, ecological and evolutionary implications and may arise from various demographic traits. Here, we use observational field data and molecular genetics to determine the genetic structure of an invasive population of monk parakeets, Myiopsitta monachus, at a range of spatial scales, and investigate the demographic processes that generate the observed structure. Monk parakeets construct large nests that can house several pairs occupying separate chambers; these nests are often aggregated within nesting trees. We determined patterns of relatedness within compound nests, within nesting trees and between trees. Spatial autocorrelation analyses of pairwise genetic relatedness revealed fine-scale genetic structure with relatives of both sexes spatially clustered within, but not beyond, nesting trees. In addition, males were more related to males sharing their compound nests than to other males occupying the same nesting tree. By contrast, males and females within compound nests were not significantly more closely related than elsewhere in the same tree, and we found no evidence for inbreeding. Adults showed high breeding site fidelity between years despite considerable disturbance of nest sites. Natal dispersal was female-biased, but dispersal distances were relatively short with some natal philopatry observed in both sexes. Sibling coalitions, typically of males, were observed amongst both philopatric and dispersing birds. Our results show significant clustering of kin within compound nests and nesting trees resulting from limited and coordinated natal dispersal, with subsequent breeding site fidelity. The resulting genetic structure has implications for social behaviour in this unusual parrot species.

Breeding dispersal distances for Myiopsitta monachus

Contains breeding dispersal distances: see ReadMe file

DawsonPell_2021_A_Breeding_dispersal.xlsx

Natal dispersal distances for Myiopsitta monachus

Contains natal dispersal distances: see ReadMe file

DawsonPell_2021_B_Natal_dispersal.xlsx

Microsatellite genotypes and nest locations of Myiopsitta monachus

Contains genotypes and nest locations for all individuals: see ReadMe file

DawsonPell_2021_C_Genotypes_spatial_autocorrelation_analyses.xlsx

Microsatellite genotypes and nest locations of Myiopsitta monachus, with only one male from each compound nest

Contains genotypes and nest locations, data includes only one male from each compound nest: see ReadMe file

DawsonPell_2021_D_Genotypes_spatial_autocorrelation_analyses_compound_males_removed.xlsx

Relatedness within compound nests and nesting trees for male Myiopsitta monachus

Contains nesting tree information and relatedness between males sharing a compound nest and between males that occupy a compound nest and males that occupy other nests in the same nesting tree. Includes all male comparisons: see ReadMe file

DawsonPell_2021_E_Compound_nests_all_males_comparisons.xlsx

Relatedness within compound nests and nesting trees for male Myiopsitta monachus excluding within chamber comparisons

Contains nesting tree information and relatedness between males sharing a compound nest and between males that occupy a compound nest and males that occupy other nests in the same nesting tree. Excluding within chamber comparisons: see ReadMe file

DawsonPell_2021_F_Compound_nests_no_within_chamber.xlsx

Relatedness within compound nests and nesting trees for male Myiopsitta monachus excluding within chamber comparisons and with random selection from multi-male chambers

Contains nesting tree information and relatedness between males sharing a compound nest and between males that occupy a compound nest and males that occupy other nests in the same nesting tree. Excluding within chamber comparisons and with random selection of a single male from a multi-male chamber: see ReadMe file

DawsonPell_2021_G_Compound_nests_no_within_chamber_random_selection.xlsx

Relatedness within compound nests and nesting trees for male-female comparison - Myiopsitta monachus

Contains nesting tree information and relatedness between males and females sharing a compound nest and between males that occupy a compound nest and females that occupy other nests in the same nesting tree. Includes all male comparisons: see ReadMe file

DawsonPell_2021_H_Compound_nests_males_vs_females.xlsx