Stripe-breasted Wrens (Thryothorus thoracicus). They have two dominant "song types".Here is example of that song type from Guayabo. Note that the birds at Guayabo often vary the pitch of this song slightly during its rendition.
Douglas Von Gausig (recordist; copyright holder), Naturesongs.com
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.