The Sonso Lagoon is one of the only remaining wetlands in the Cauca Valley and one of Colombia’s best wetland birding localities. The reserve sits at 950 m (3,100 ft), encompasses 2,000 ha (5,000 ac), and is home to the near-endemic Scrub Tanager and Bar-crested Antshrike. Apical Flycatcher and Grayish Piculet are two birds that are relatively easy to see in the tropical dry forests surrounding the lagoon. More than 160 species have been recorded at the Sonso Lagoon, including Ruby Topaz, Jet Antbird, Great Antshrike, Spectacled Parrotlet, Crested Caracara, Little Cuckoo and the secretive and very vocal Striped Cuckoo. The wetland is teeming with aquatic birds, including Blue-winged Teal, Fulvous and Black-bellied Whistling-Ducks, Limpkin, Anhinga, Blackish Rail, and Black-crowned Night-heron. Always a treat but needing a bit of luck, views of Horned Screamer are the rare Comb Duck are sometimes possible.
The Cauca and Magdalena Valleys in Colombia provide an escape from mountainous birding in elevations ranging from 200-1,200m (650-4,000 ft), and as such their natural vegetation comprises open woodland, dry forest and arid scrub. The Cauca Valley is the narrower of the two, and harbors species such as the endemics, Grayish Piculet and Apical Flycatcher, as well as specialties such as Jet Antbird, Blackish Rail, Least Bittern, Horned Screamer and the near endemic Bar-crested Antshrike. Several Important Bird Areas (IBAs) protect the last remaining wetlands and dry forests of the valley, and are a birders dream. The Cauca Valley is bordered by the western Andes to the west and the Central Andes to the east.
Velvet-fronted Euphonia is restricted to the Magdalena Valley, which is narrower and drier on the south end, becomes humid in the mid-valley and opens up to a network of vast wetland at the northern end. Targets of the Magdalena Valley include the endemics White-mantled Barbet, Beautiful Woodpecker, Antioquia Bristle-Tyrant, and Blue-billed Curassow.