Re: Why do some birds hop only, and others walk mostly and hop a little?

Ron,

I am not aware of any 'official' published explanation of this observation, 
but I read the following idea on a trackers website.

The walking birds are usually the larger, ground dwelling birds, like 
pheasants, although they can hop if they want to.

Hopping birds are usually the tree dwellers, especially small birds like 
chickadees.  This is presumably because there is not much opportunity to 
walk among the twigs of a tree, so they specialise in hopping.

The birds which seem to hop and walk equal amounts are birds which 
spend some time in each habitat - the European blackbird (Turdus 
merula) comes to mind, similar to the American robin.

The answer may also have something to do with relative efficiency of the 
two gaits.  Hopping might be more efficient for birds up to a certain 
weight, but some choose to walk because they need the extra precision of 
movement.  Just the sort of question an engineer might be able to answer !