We provide the first documentation ofLaterallus exilis in Costa Rica. Because of its secretive nature, little is known about this species. We describe the coloration of its soft parts and contrast its vocalizations with those of L. albigularis, a common and sympatric congener. In Costa Rica, L. exilis apparently breeds during the rainy season. Contrary to previous beliefs, L. exilis appears
... [Show full abstract] locally common and widespread in Costa Rica. Although it appears most common in wet pastures, its habitat preferences shift seasonally, in response to fluctuating water levels. Because L. albigularis occupies the same types of habitat, we looked for evidence of interspecific interactions. We found that each species responded to playbacks of each other's vocalizations and that seasonal habitat shifts appeared reciprocal. Thus, we suggest that the coexistence of these rails is a dynamic process, mediated by interspecific territoriality and/or aggression.