The Black-throated Trogon is a widely colored bird. For the male, the green head and upper chest, black throat, yellow bill and underparts, blue orbital skin, gray wings and barred black and white under tail is strikingly diverse. The female is pretty similar, but with brown upperparts and throat. In low light, it might be mistaken for a Gartered Trogon, but the Gartered has yellow orbital skin on male, and finer barring on the undertail.
The individual below was photographed in La Selva Biological Station, during a Birdwatching trip with Asociación Ornitológica de Costa Rica, on October 15th, 2017. I spent more than half an hour with the bird, photographing various angles and getting some video of him. It was found at the other end of the bridge connecting the reception to the research area, perching on a branch that was a bit at a lower level than the bridge.