I present the historical details associated with early 20th century descriptions of Aplomado Falcon subspecies. I identify potential weaknesses in these diagnoses that justify re-examination of traditional taxonomy, and stress that climate change, habitat modification and large-scale reintroduction efforts may have altered or eliminated any valid subspecies boundaries that once existed. I recommend that conservation efforts in the Northern Hemisphere focus on the Chihuahuan Desert of Mexico where Aplomado Falcons have declined severely in recent years.