Updated: Apr 2
Out of 100 randomly sampled (Random Lists 2021) bird species, ~62% are colored darker at the wing tip than the the lower breast, ~32% are the same color at both locations, and ~6% are colored brighter at the wing tip than they are on the lower breast. The list of birds sampled is included below, with breast color and wing tip color following in parentheses (breast color—wing tip color). Assuming the color white to relate to colors at the brighter, red/orange/yellow part of the rainbow spectrum and black to be associated with the blue/violet end, most birds are colored in such a way that their colors follow the rainbow from their center to the extremities. Only about 6% of birds appear to be colored in an opposite, antirainbow fashion. Birds generally find the former patterning more attractive. The results are probably similar for many other animals such as butterflies and whales. The explanation for the consistency across species, which seems to require something universal about the brain, is most likely a universal bias favoring the thermoaesthetic mixtures dark—dynamic and bright—static over the thermological combinations bright—dynamic and dark—static.
Dark—dynamic and its opposite bright—static, as well as dark—fluid and bright—order are observable throughout the animal world in the coloration patterns and shapes of numerous types of animals, particularly birds and butterflies. It’s true in a large majority of bird species that the tip of the wing, if not the entire wing, parts which must appear more dynamic during interactions between birds, are a darker color (e.g., black, blue, brown) than the breast, or more central part of the bird, which must appear less dynamic in bird interactions. This is a pattern which, given its ubiquity, is very difficult to explain in terms of the currently most popular natural and sexual selection theories.
It can be observed in North American bird coloration on the Audubon website. All living penguin species appear to be colored in this way except for the White-flippered penguin Eudyptula minor albosignata, whose wings have a white outline. All of the species of manakins (Pipridae) appear to be this way as well. All of the butterflies in the genus Morpho have dark coloration on the tips of the front wings. The giant panda Ailuropoda melanoleuca also fits this pattern, assuming its arms and legs move more than the rest of its body.
Thus a curiously large proportion of animals appear to be colored with darker extremities. Further examples include Tufted Capuchins (Sapajus apella), Golden-bellied Capuchins (Sapajus xanthosternos), Golden-backed Uakaris (Cacajao melanocephalus), Roloway Monkeys (Cercopithecus roloway), Blue Monkeys (Cercopithecus mitis) with blue bodies and black arms, Mona Monkeys (Cercopithecus mona), De Brazza's Monkeys (Cercopithecus neglectus), and the Proboscis Monkey (Nasalis larvatus) with blue arms and legs. Bats (Chiroptera) appear to be colored with brighter bodies and darker wings in general.
Random bird sample data: Rainbow Lorikeet (red—black), Laughing Kookaburra (white—black), Ruddy Duck (black—black), Nicobar Pigeon (light blue—dark blue), Snowy Owl (white—mottled), Scaly-sided Merganser (white—black), Black-faced Dacnis (teal—dark blue), Grosbeak Starling (black—black), American Kestrel (white—black), Keel-billed Toucan (yellow—black), Black-faced Tanager (light blue—black), Bald Eagle (brown—brown), White-tailed Trogon (blue—black), Crested Wood Partridge (black—black), Augur Buzzard (white —black), Golden Conure (yellow—green), Palm Cockatoo (black—black), Ringed Teal (pink—red ), Fairy Bluebird (black—black), Southern Bald Ibis (black—black), Golden-crested Mynah (black—black), Pied Imperial Pigeon (white—black), Curl-crested Aracari (yellow—black), Gouldian Finch (purple—green), Hadada Ibis (mottled—black), Green Woodhoopoe (green—dark blue), Indian Runner Duck (white—black), Military Macaw (green—green), Bearded Barbet (red—black), Red Bishop Weaver (black—mottled), Wattled Curassow (black—black), Harris's Hawk (black—black), Steller's Sea Eagle (black—black), Scarlet Ibis (pink—black), Crested Coua (red—black), Guira Cuckoo (tan—black), Malayan Great Argus (red—mottled), European Starling (mottled—mottled), Burrowing Owl (white—mottled), Green Aracari (yellow—black), Hyacinth Macaw (blue—blue), Javan Pond Heron (white—black), Palawan Peacock-pheasant (black—blue), Orange Bishop (black—black), Golden-breasted Starling (yellow—black), White-necked Raven (black—black), Sunbittern (white—mottled), Lanner Falcon (white—grey), Southern Ground Hornbill (black—black), Victoria Crowned Pigeon (purple—blue), Crested Oropendola (black—black), Grey-winged Trumpeter (blue—white), Meyer's Parrot (green —yellow), Pekin Robin (red—grey), White-bellied Go-away-bird (white—black), Guam Kingfisher (pink—blue), Inca Dove (white—brown), Green Singing Finch (yellow—black), Melba Finch (mottled—brown), Sun Conure (oragne—green), Yellow-naped Amazon (light green—dark green), Troupial (orange—black), Silver Gull (white—grey), Canary (yellow—black), Bridled White-eye (yellow—green), Eurasian Eagle-Owl (mottled—mottled), Cut-throat Finch (mottled—gray ), Eastern Screech Owl (white—brown), Red-fronted Macaw (green—blue), Giant Cowbird (black—black), Rhinoceros Hornbill (black—black), Andean Condor (black—black), Palm Tanager (grey—black), Inca Tern (grey—grey), Blue-crowned Motmot (orange—green), Spangled Cotinga (blue—mottled), Scarlet-headed Blackbird (black—black), West Indian Whistling Duck (red—mottled), Boat-billed Heron (brown—white), Raggiana Bird-of-Paradise (red—red ), Rosybill Pochard (black—grey), Roseate Spoonbill (white—pink), White-eared Catbird (yellow—green), Bali Mynah (white—black), Dhyal Thrush (white—black), Cattle Egret (white—white), Brazilian Tanager (red—black), Taveta Golden Weaver (yellow—mottled), Red-legged Honeycreeper (blue—black), Blue-fronted Amazon Parrot (green—black), Greater Roadrunner (white—mottled), White-crested Laughing Thrush (white—black), Yellow-hooded Blackbird (black—black), American Crow (black—black), Black Vulture (black—black), Hooded Merganser (white—black), Purple-throated Fruit Crow (black—black), Black-headed Gonolek (red—black), African Grey Parrot (white—black), African Penguin (white—black).
Random Lists. “Random Bird Species - List of Random Birds.” 2021. www.randomlists.com/birds.