Ok, checked out the Wiki-Quicki. They are described as Near-passerine, ie closely related to the passerines or perching bird. Most often they are ground feeders. I'm sure most birds, except maybe the swift and other bug-catchers would rather not fly if they don't have to. BUT! Pigeons ARE BUILT for SPEED. I have already metioned the powerful breast muscles and the fact that the legs are set back. But, it turns out that their legs are set farther back than most other birds. Form follows function and the function of legs set far back is to reduce drag in flight. Again, these birds are built for flight and speed. The co-incidence that they are related to the late, great Dodo and that the Dodo was flightless is just a matter of time and chance. Like other South Seas birds, most notably the Kiwi, it found itself on an island with no predators in its niche. It didn't need to fly or migrate to survive so it lost that unneccessary function. Point here is that ALL birds would probably perfer to be flightless. Quail, chickens and turkeys are much farther down this path than pigeons. These gallinaceous birds have even more powerful breast muscles than those of the columbidae(dove, pigeons) order but their legs are closer to their centers of gravity which is to say they stand more erect. As form does follow function, this is because they spend more time on the ground. They have short stubby wings, stiff feathers that come to a point. They are powerful fliers for short distances and long glides, natures little dragsters!

The pigeons wings are long and pointed and flexible which is another way to say they are distance fliers. If a ground predator spooked them, they are not going to see them again for a long time. Narrow tapered wings which come to a point are nature's design for long swift flight and the flexibility is for highspeed manuevering: eluding the pigeon hawks. These are nature's Indy cars! It's why people raise "racing" pigeons.

The head bob is peculiar to all members of this order. And like a good researcher I have just now read the artcile in queston!and pretty much justified my pointifications ( I did study orinthology a little in my youth under the tutelage of the late Edward Butts, Head Naturalist at the Grand Tetons National Park, ret.). (OK, no T&A jokes please)!