As a species, Red-tails are only partially migratory, some populations remain quite far north throughout the year. Prey abundance probably influences timing and distance of migration more than any other factor. In general, eastern red-tails are among the latest migrants, high counts usually occur in mid to late November, while western populations yield highest counts in October. Because they occur as winter residents over much of the U.S., It is difficult to draw conclusions about their migratory patterns based on hawkwatch count data. Most of what we will eventually learn about seasonal and lifetime movements of this species will come from studies using radio telemetry (tracking individuals that have been equipped with a small transmitter), and data from recovery of banded birds.