What is a common characteristic of strictly bird-catching raptors?

The common characteristic of strictly bird-catching raptors is having long toes. This adaptation allows these raptors to effectively grasp and secure their prey during hunting. Birds are often agile and can quickly maneuver in flight, so having longer toes facilitates a stronger grip on the bird once caught. This characteristic is crucial for maintaining control and preventing escape.

In the context of raptor anatomy, other factors, such as beak structure and wing size, also contribute significantly to their hunting prowess, but the length of the toes is particularly important for bird-catching species. While short or medium-sized toes might be suitable for other raptors that hunt different types of prey or have varying hunting strategies, the longer toes found in strictly bird-catching raptors are specifically evolved to enhance their ability to catch and hold onto birds during flight.