This one is quite funny to annoying.
In Colombia, "Polyborus plancus" featured in the Country's only field guide for almost 25 years (Hilty & Brown 1986, p115). During most of those two and a half decades, it was mostly known as "Caracara cheriway" by other ornithologists - but a large body of publications built up in Colombian ornithology using P plancus nonetheless, as do historical works. The field guides since 2010 all used C. cheriway, following SACC. Now this one will be called "Caracara plancus", a combination of the two previous versions. The birds, now moving on to their third Latin name, still look the same to me as they did when I first went to Colombia in the mid 1990s.
The separation of these two "species" at unspecified localities somewhere in the middle of Amazonia never made much sense and I suppose this change must be right. But taxonomists here have caused much confusion - it's a poster child for unjustified tinkering with taxonomy or an advertisement for using English names and abandoning binomial nomenclature!!