1 –––––––––––––––––––––––––––––––––––––––– © 2019 Nordic Society Oikos. Published by John Wiley & Sons Ltd Subject Editor: Jan Engler Editor-in-Chief: Tomas Alerstam Accepted 4 November 2019 00: 1–24, 2019 doi: 10.1111/jav.02242 JOURNAL OF AVIAN BIOLOGY www.avianbiology.org Journal of Avian Biology 2020: e02242 Te interaction between ecology and evolution, particularly with regard to speciation processes, remains a main topic of scientifc research. Andean hummingbirds have undergone a remarkable radiation, with many species exhibiting patchy distributions and, in some cases, taxonomic controversy. An example is the sapphire-vented pufeg Eriocnemis luciani; ssp. baptistae, luciani and meridae, which some authors merge with the coppery-naped pufeg E. sapphiropygia; ssp. catharina and sapphiropygia. Each group is distributed either north or south from the Huancabamba Depression, the major biogeographical barrier within the tropical Andes. We investigated whether these subspecies share some niche characteristics despite their geographical separation and determined their meaning in the context of the speciation process of trochilids in the tropical Andes. For each subspecies, we performed geographical predictions and paired tests of niche conservatism in environmental space. Geographical predictions included separate regions for subspecies catharina and sapphiropygia, while the predicted regions for subspecies luciani and baptistae greatly overlapped. Te E. l. luciani model predicted a single pixel near to the potential area of E. l. meridae, known only from a unique, old record. Subspecies luciani and baptistae exhibited the greatest niche overlap among the pairs of taxa for most variables. However, our results clearly indicated niche divergence for the four members of the E. luciani–sapphiropygia complex, independent of the similarities or slight dissimilarities in their respective backgrounds, indicating that other forces in addition to variation in environmental parameters, such as natural selection or genetic drift, are driving the radiation of these hummingbirds. Tis fnding coincides with the unusually high speciation rates reported for Andean hummingbirds. Tus, the currently accepted taxonomy within the E. luciani– sapphiropygia complex may be even more convoluted than indicated by previous studies. Hence, the results of our study are a wakeup call to include the exploration of lineage diversifcation in biodiversity-related eforts. Keywords: Eriocnemis, niche conservatism, niche modelling, speciation, tropical Andes Niches and radiations: a case study on the Andean sapphire-vented puffleg Eriocnemis luciani and coppery-naped puffleg E. sapphiropygia (Aves, Trochilidae) Paolo Ramoni-Perazzi, Karl-L. Schuchmann, André Weller, Irma Alejandra Soto-Werschitz and Marcelo Passamani P. Ramoni-Perazzi (https://orcid.org/0000-0001-9182-3798) ✉ (rpaolo1967@gmail.com), I. A. Soto-Werschitz and M. Passamani, Laboratory of Ecology and Conservation of Mammals, Federal Univ. of Lavras (UFLA), PO Box 3037, Lavras, Minas Gerais, 37200-000, Brazil. PRP and IASW also at: Dept of Biology, Sciences Faculty, Univ. of the Andes, 5101 Merida, Venezuela. – K.-L. Schuchmann and A. Weller, Zoological Research Museum A. Koenig (ZFMK), Dept. of Vertebrates/Ornithology, Bonn, Germany. KLS also at: Natl Inst. for Science and Technology in Wetlands (INAU), Federal Univ. of Mato Grosso (UFMT), Cuiaba, MT, Brazil. AW also at: Bornheim, Germany. Article