Columbiforms may be roughly divided into seed and fruit-eating forms.
A highly developed orbital ring has appeared independently in several unrelated lines of columbiforms. It is to be found, for example, in the diminutive Diamond Dove (Geopelia cuneata) of Australia, the Bare-eyed Pigeon (Columba corensis) of South America, the Speckled Pigeon (Columba guinea) of Africa and in the Blue Pigeons (Alectroenas spp.).
The Columbiformes have radiated into species with enormous extremes in size ranging from the Common Ground-dove (Columbina passerina) which weighs 31 g to the crowned-pigeons (Goura spp.) of New Guinea which weigh 2000 g.
Occipital crests have evolved independently in several unrelated lines of columbiforms; for example, the Jamaican Crested Quail-dove (Geotrygon versicolor) possesses an occipital crest as does the Thick-billed Ground-pigeon (Trugon terrestris) of New Guinea (Coates 1985) and the Sulawesi race (paulina) of the Green Imperial-Pigeon (Ducula aenea) (L.
At least two cases of flightlessness in columbiforms from islands have occurred in history, namely the Dodo (Raphus cucullatus) of Mauritius and the Solitaire (Pezophaps solitaria) of Rodrigues Island (Greenway 1958).
If such rapid evolution is typical of the family then it is no wonder that columbiforms have been so successful as colonizers in so many diverse habitats.
Goodwin (1960) reviewed the subject of sexual dichromatism in columbiforms and noted that species graded from color monomorphism between the sexes (as in P.
The elaborate differences in markings and color-patterns between the sexes in columbiforms have most likely arisen through a number of intermediate steps mediated by accumulation of micromutations.
Both sexes participate in incubation in columbiforms. Males usually incubate from mid-morning to mid-afternoon, whereas females incubate from mid-afternoon through the night into the next morning (Skutch 1964).
The facts that in wild Rock Doves checker and two-bar are (inherited as) two discrete characters, and that in other taxa construction of hybrids produces character states present in related taxa, lend support to Whitman's (1919) suggestion that checker is an old character state in Columba livia and columbiforms in general.
Moreover, recent studies on the phylogenetic relationships of the columbiformes allow mapping of morphological and behavioral traits to let us know how often these traits have appeared in the family.
Nuclear and mitochondrial genes contain similar phylogenetic signal for pigeons and doves (Aves: Columbiformes).