Immigration and local recruitment play a central role in determining the growth rate of breeding populations. Unravelling these processes in newly-established populations is of great importance to increase understanding of how species change their distributions in response to global change. In this study, these processes were analyzed through the monitoring of a glossy ibis population in Doñana from the settlement of the colony in 1996. The impressive growth of this population due to immigration (from 7 couples to over 8,000 in twenty years) has directly fueled the expansion of the species in the Mediterranean area and Western Europe. In terms of metapopulation, the Doñana population has rapidly changed its status from sink to source population, thanks mainly to immigration. The pull factors in Donana must have been very significant considering the high values of local demographic parameters such as reproductive success (average of 2.1 fledglings per pair) and the rate of self-recruitment which was particularly high (>80%)  for first-year individuals. Finally, this study highlights as immigration not only support populations at the limit of its range, but may also indirectly play a key role in the expansion process of a species. informacion[at]ebd.csic.es: Santoro et al (2016) Immigration enhances fast growth of a newly-established source population. Ecology doi:10.1890/14-2462