Assessing the geographic range of Black‐fronted Ground‐Tyrants (Muscisaxicola frontalis) using extralimital and winter range occurrence records and ecological niche modeling

Estimating the geographic range of a species can be complicated by insufficient occurrence data and a lack of information about range limit determinants. Accurate estimates of species distributions are needed to assess the impacts of anthropogenic actions and for exploring evolutionary and ecological processes that maintain biological diversity. After documenting several extralimital locations for Black-fronted Ground-Tyrants (Muscisaxicola frontalis; Tyrannidae), we questioned the accuracy of the current winter range estimate. We provide specimen and observation records from central and southern Peru that represent new information about the winter distribution of Black-fronted Ground-Tyrants. We used ecological niche models generated from new extralimital records and records from the winter range to assess the current range estimate. We also tested winter and extralimital niche models for model equivalency using a resampling technique available through Maxent and ENM Tools. Niche models developed with locations from the winter range predicted with high probability (>90%) the area of the extralimital records. Reciprocally, niche models developed with the extralimital locations predicted the majority of the winter range locations, although the probability was lower for some locations and the most southerly points were not included in the prediction. The test for model equivalency did not distinguish the two models, suggesting the possibility that the extralimital records were from poorly sampled areas of the true winter range. Smaller scale habitat associations of Black-fronted Ground-Tyrants, such as a preference for sparsely vegetated slopes, were documented that were more specific than published accounts. Finally, we present the first case of frugivory in Muscisaxicola with the identification of Cumulopuntia boliviana ignescens (Cactaceae) seeds and pericarp in all five stomach samples of Black-fronted Ground-Tyrants collected in southern Peru.