Unraveling the genetic parameters, social relationships, and conservation aspects of a group of <i>Touit melanonotus</i> (Brown-backed Parrotlet)

ABSTRACT The genetic parameters underlying the biological and behavioral traits of most Neotropical parrots are poorly understood due to limited sampling. Touit melanonotus (Brown-backed Parrotlet) is a globally Near Threatened, rare, unobtrusive, and small-bodied parrotlet endemic to the Atlantic Forest of Brazil. In 2020, a flock of T. melanonotus collided with a window at São Paulo International Airport in Guarulhos, São Paulo State, Brazil, resulting in the death of 29 individuals. We aimed to assess the genetic diversity of this flock, estimate the effective population size, and conduct a pairwise kinship analysis to explore flock formation, behavior, and the familial structure of this species. To that end, we used single nucleotide polymorphisms derived from genome-wide ultraconserved elements of the flock. We observed a higher-than-expected genetic diversity (t = 7.243, P ~ 0) and no evidence of inbreeding depression, with F ranging from –0.406 to –0.110 (χ2 = 37.687, P = 0; χ2 = 4.217, P = 0.040, respectively). We identified evidence of a historical decline in the effective population size of wild individuals, and kinship analysis indicated the presence of different familial nuclei, with multiple individuals pairing with more than one partner in the sampled group, which is strong evidence for extra-pair copulation that may help maintain heterozygosity levels in this declining population. Based on our genetic parameters, we found no immediate or urgent need for genetic management as a conservation action. We recommend that conservation efforts focus on habitat maintenance and the restoration of the Atlantic Forest, a highly degraded and fragmented biome.