Like most species of hummingbird, Peruvian Sheartail readily adapts to cages, so it is suitable for captive studies. The natural history of Peruvian Sheartail is poorly known. In the Azapa Valley of northern Chile it is now locally abundant, such that catching significant numbers of birds for behavioral or ecological studies would be feasible. For instance, the greatly elongated tail-feathers of the male apparently are a visual signal during its courtship displays, and these feathers are often worn, abraded, or broken. Does this affect mating success of males? Basic aspects of its life history are unknown, such as timing of molt, and whether this species really has two breeding seasons per year (see Reproduction) should be better documented.
Better understanding of the ecological relationships between Peruvian Sheartail and Chilean Woodstar (Eulidia yarrellii) in northern Chile may be of critical importance for conservation efforts to protect the endangered Chilean Woodstar. The range of Chilean Woodstar has contracted in the past four decades, at the same time that the Peruvian Sheartail has expanded its range south (Estades et al. 2007, van Dongen et al. 2013). One of the hypotheses for this decline is ecological competition (e.g. over food or habitat) between the two species (van Dongen et al. 2013). While disentangling this hypothesis from the effects of habitat loss or alteration may not be possible, the evidence suggests that Chilean Woodstar is dominant over the Peruvian Sheartail in 1 on 1 interactions (van Dongen et al. 2013). Whether the Peruvian Sheartail nevertheless outcompetes the Chilean Woodstar due to sheer numbers deserves further attention.
Another potential interaction between the species is hybridization between Peruvian Sheartail and Chilean Woodstar. Clark et al. (2013) describe a hybrid whose mother was a woodstar, and hypothesize it may represent an Allee effect of the population crash of the Chilean Woodstar. While van Dongen et al. (2013) have found no evidence of past introgression between the two species, further hybridization between the two species would be expected to result in introgression in the future.