What is smaller a kestral and a Merlin?

The Merlin is generally smaller than a Kestrel. Adult Merlins typically measure about 9.1 to 11.4 inches in length, while Kestrels range from about 9.8 to 12.2 inches. However, the size difference can vary depending on the specific species and individual variations. Overall, Merlins are considered more compact and robust compared to Kestrels.