Santa Rosa NP
Santa Rosa National Park is a fairly large national park in the northwest corner of Costa Rica near the Nicaraguan border. Most birds considered Guanacaste specialties can also be found here.
The park is a good place for birds that inhabit dry scrub, but there is also an evergreen gallery forest along one of the trails which is particularly good birding. Long-tailed Manakin, Rufous-capped Warbler, Barred Antshrike, and an isolated population of Black-crowned Antshrikes can be found here. I found a Nutting's Flycatcher in the drier habitat.
The more typical Guanacaste birds such as Turquoise-browed Motmot and Black-headed Trogon are fairly easy here.
Santa Rosa also has some of largest Guanacaste lizards in the country.