To explore scientific mobility patterns, we leverage a rich bibliometric dataset on Taiwanese academia. We investigate the movement and productivity of 21,051 highly active researchers who published while affiliated with Taiwanese higher education institutions based on 30 years' worth of publication and affiliation records from 1991 to 2020. The analysis shows evidence of brain drain in Taiwan since the 2010s, with the U.S. the top destination for researchers moving from Taiwan (as well as the largest source of inbound researchers). China comes a close second to the U.S. as the top destination for outbound scholars. Studying how Taiwan's universities recruited talent after the country adopted the 2005 excellence initiative, we discover that the numbers of scholars recruited by World Class Universities (WCUs) and non-WCUs surprisingly converge with WCUs exhibiting a dramatic decrease in new recruits. Our evidence uncovers that inbound scholars, after their move, are more productive than non-mobile colleagues; however, this effect declines over time. We discuss implications for the study of excellence initiatives, their (un)intended consequences, and mechanisms of talent circulation that greatly impact research production and research university development.