Found this great animation and some diagrams demonstrating the amazing grip of owls.
An owl's ability to catch and hold on to pretty is vital to its survival. It's also important for other things, such as not falling off a tree it's sleeping on! So how does this work?
There are no muscles in the foot. The only thing that moves the talons is a system of tendons. When an owl swoops in on pretty or a perch, it comes in with legs extended in front of itself.
In this outstretched posture, the tendons are opened. As the feet strike the target, impact pushes the legs into the body. This movement makes the tendons automatically snap the talons closed. As body weight is applied, the grip is locked in place. Only by purposefully removing weight from the foot or consciously extending the leg does the foot open. This way, an owl standing in prey or a branch cannot let go unless it chooses to or is physically overpowered.
Owl grip is no joke. Other than just the talons being able to stab, their grip can rival that of the jaws of some of the large dog breeds. That strength, plus 8 built in daggers is a killer combo.
Images originally by arsanotomica, except for the Barn Owl. There's a few more anatomical terms at the link if you're interested.
