A male Resplendent Queztal, for which we had to wait a while (and make two visits) near a known nest cavity. The female was more cooperative, but the male's long streamers (which are the upper tail coverts, covering the normal-length black tail), and scarlet red belly were well worth the wait
Black Guan in the gorgeous Costa Rican Oak forest below Cerro de la Muerte.
A male Slaty-tailed Trogon a few feet away, starting to excavate a nest cavity in a termite nest up in a tree. He would make a hovering sally at the nest, dig with his bill for a few seconds, and then land nearby (with the female supervising overhead), and occasionally wipe his bill to remove the termites clinging to his rictal bristles. This was at Bosque del Rio Tigre on the Osa Peninsula.
A Glorious Blue Skipper, Paches loxus, also at Bosque del Rio Tigre. This has to be one of the most beautiful skippers, most of which are various shades of brown.
This is a male Violet-crowned Woodnymph at El Tapir gardens below Braulio Carrillo National Park. We saw four Snowcaps here as well (photos at Facebook and WINGS website), and it was interesting to see one deftly evade a very territorial woodnymph who just couldn't fly or maneuver as fast. The Snowcap merely rose above the other hummer whenever it tried to chase it away and then he would continue to feed at the porterweed nearby, as if he were daring the woodnymph to just try.