Using these two shots as a basis, part of the problem may be your choice of focus targets. Here you are trying for the head and beak. In these two examples, the head is very small which may lead the camera to pick something else by mistake. If you were to pick the body where it joins the neck you would have a bigger target with good contrast.
Upgrading the lens to something longer (55-300mm, 70-300mm) would also help with making the heads bigger in the focus point.
---------+---------+---------+---------+ Joseph K Seattle, WA, USA