Primary feather morphology varies greatly across Columbidae.
In a museum survey of over 500 specimens across 22 genera and 66 species and in a broad literature survey I identified several distinct feather morphologies found in pigeons and doves in a variety of outermost primary feathers. These morphologies vary greatly within genera, and even within species. Some researchers have suggested that these unique feathers have been evolutionarily co-opted for sound-production, but only two feathers have actually been tested ("yellow" in Ocyphaps lophotes by Clark and Prum 2015, and "purple" in Columba livia by Niese and Tobalske 2016). In both of these instances, feathers produced tones via aeroelastic flutter. Only the Crested Pigeon (Ocyphaps lophotes) is known to interpret threat-related information from these tones, which has led researchers to identify them as "non-vocal alarm signals."
The presence of a unique P10 morphology varies greatly within the Fruit Doves (Ptilinopus spp) and allies.
An ancestral state reconstruction (Mesquite v3.5, Maddison and Maddison, 2010; Mk1 rate model, Lewis 2001) suggests that a modified P10 morphology has independently evolved 5 or 6 times within the polyphyletic genus Ptilinopus, but evidence does not suggest that, once gained, the morphology has ever been lost. For a complete ASR of this modified P10 morphology across all Columbidae, click here.
(Niese in prep; Cibois et al. 2014, 2017; Mahler and Tubaro 2001)