The edibility of bird legs improves dramatically when you remove the tendons.  This makes the legs more tender and user-friendly leg. Below are a few photos showing the process on a mallard. On birds bigger than mallards, this becomes a two person job as the tendons are quite strong. Removing the tendons from a turkey leg requires a pair of pliers and near Herculean strength.

Using a sharp knife, cut through the rubbery skin on the duck’s leg right over the leg joint. Be very carful not to nick the meat or tendons beneath the skin.

Pop the joint, like snapping a stick. Wiggle the leg a bit to work the tendons clear of the popped joint.

Take a firm hold of the bird’s thigh with one hand and of the foot with the other. Now pull slowly and firmly. The tendons should separate from the hip joint and pull out with the foot.

A Great Way to Prep Ducks
Here’s a favorite way of mine to handle ducks, especially puddle ducks and the better tasting divers such as scaup. It also works well with upland game birds, and I’ve even done street pigeons this way.

Start out with a gutted and plucked bird.

Slice down each side of the ridge-like breastbone, from the top of the breast to the bottom.

Continue filleting the breast downward. Pop the ball joint of the hip bone, then work your way down to the skin of the back and slice through that, freeing half of the bird from the breast plate.

This half is ready to cook. Proceed to the second half.