The Great American Biotic Interchange (GABI) was a key biogeographic event in the history of the Americas. The rising of the Panamanian land bridge ended the isolation of South America and ushered in a period of dispersal, mass extinction, and new community assemblages, which sparked competition, adaptation, and speciation. Diversification across many bird groups, and the elevational zonation of others, ties back to events triggered by the GABI. But the exact timing of these events is still being revealed, with recent studies suggesting a much earlier time window for faunal exchange, perhaps as early as 20 million years ago (Mya). Using a time‐calibrated phylogenetic tree, we show that the jay genusCyanolycais emblematic of bird dispersal trends, with an early, pre‐land bridge dispersal from Mesoamerica to South America 6.3–7.3 Mya, followed by a back‐colonization ofC. cucullatato Mesoamerica 2.3–4.8 Mya, likely after the land bridge was complete. AsCyanolycaspecies came into contact in Mesoamerica, they avoided competition due to a prior shift to lower elevation in the ancestor ofC. cucullata. This shift allowedC. cucullatato integrate itself into the Mesoamerican highland avifauna, which our time‐calibrated phylogeny suggests was already populated by higher‐elevation, congeneric dwarf‐jays (C. argentigula,C. pumilo,C. mirabilis, andC. nanus). The outcome of these events and fortuitous elevational zonation was thatC. cucullatacould continue colonizing new highland areas farther north during the Pleistocene. Resultingly, fourC. cucullatalineages became isolated in allopatric, highland regions from Panama to Mexico, diverging in genetics, morphology, plumage, and vocalizations. At least two of these lineages are best described as species (C. mitrataandC. cucullata). Continued study will further document the influence of the GABI and help clarify how dispersal and vicariance shaped modern‐day species assemblages in the Americas.