cattle tyrant

maybe a tropical kingbird

I would say Cattle Tyrant, as opposed to the super-abundant Tropical Kingbird. This bird has yellow undersides from chin to vent, whereas TKs would have a more gray upper breast. Cattle Tyrants also have slighter bills, and like to walk around on the ground. Check out the range of Cattle Tyrants, which have a much more restricted range than the ubiquitous TKs. Range is very important in Colombia because of the vast difference in habitat types, but TKs are generalists and use many habitats.