Is the resident subspecies of the Eurasian spoonbill in Mauritania, Platalea leucorodia balsaci , threatened by introgression of genes from the migratory nominate subspecies leucorodia ?

Research indicates that the resident subspecies of the Eurasian spoonbill, Platalea leucorodia balsaci, in Mauritania's Banc d'Arguin National Park is not threatened by genetic introgression from the migratory nominate subspecies, leucorodia. Despite observed gene flow—evidenced by yellow-tipped bills in over half of the marked balsaci population—residency remains intact, as no resightings of these birds have occurred outside Banc d'Arguin. The study suggests that balsaci should be categorized as Vulnerable on the IUCN Red List due to its small population size and habitat threats from sea-level rise. The research combines genetic analysis, morphological observations, and behavioral monitoring to assess potential hybridization risks while emphasizing the need for continued surveillance of this unique subspecies.

Piersma, T., Camara, M., de Goeij, P., Loos, B., Oortwijn, T., & El-Hacen, E.-H. M. (2025). Is the resident subspecies of the Eurasian spoonbill in Mauritania, Platalea leucorodia balsaci , threatened by introgression of genes from the migratory nominate subspecies leucorodia ? Oryx, 59(5), 579–583. https://doi.org/10.1017/s0030605325101737