I wonder if there is any chance this could be a Carib Grackle. The tail and bill do seem a little small. Neither is supposed to be in Puerto Boyaca and the Magdalena valley, but the Great-tailed Grackle doesn't have to cross a mountain to get there, and is known to be expanding its range (with deforestation). UPDATE, the Carib Grackle has indeed moved over (around actually along the Caribbean coast) the eastern Andean chain.
Anguilla,Antigua and Barbuda,Barbados,Brazil,Colombia,Dominica,French Guiana,Grenada,Guyana,Montserrat, Netherlands Antilles,Saint Kitts and Nevis,Saint Lucia,Saint Vincent and the Grenadines,Suriname,Trinidad and Tobago,Venezuela,
IOC 13.1 Subspecies
Group
Subspecies
Breeding Range
guadeloupensis
nc Lesser Antilles
inflexirostris
St. Lucia (c Lesser Antilles)
luminosus
Grenada and the Grenadines (s Lesser Antilles) and Los Testigos (off ne Venezuela)
orquillensis
Los Hermanos (off ne Venezuela)
insularis
Margarita I. and Los Frailes (off ne Venezuela)
lugubris
Trinidad, n Venezuela, the Guianas and ne Brazil
contrusus
St. Vincent (s Lesser Antilles)
fortirostris
Barbados (s Lesser Antilles); introduced to Antigua, Barbuda and St. Kitts (c Lesser Antilles)
Africa (entire continent rather than south of Sahara)
AN
Antarctica
AO
Atlantic Ocean
AU
Australasia (Wallacea (Indonesian islands east of Wallace's line), New Guinea and its islands, Australia, New Zealand and its subantarctic islands, the Solomons, New Caledonia, and Vanuatu)
PAL
Eurasia (Europe, Asia from the Middle East through central Asia north of the Himalayas, Siberia and northern China to Japan)
IO
Indian Ocean
LA
Latin America (Middle and South America)
MA
Middle America (Mexico through Panama)
NA
North America (includes the Caribbean)
NO
Northern oceans
OR
Oriental Region (South Asia from Pakistan to Taiwan, plus Southeast Asia, the Philippines, and Greater Sundas)