Breasted Birds

Although birds do not have external breasts in the sense that mammals do, it still seems to me that birders (and ornithologists, too) exhibit an inordinate obsession with the breasts of their quarry. In support of that premise, I note that the common English names of no fewer than 254 species of birds worldwide are based on the size, shape, pattern, or color of their breasts (from Clements 2000):

Apricot-breasted Sunbird
Ash-breasted Antbird, etc. (4 species)
Azure-breasted Pita
Bar-breasted Firefinch, etc. (3)
Bay-breasted cuckoo & warbler (2)
Black-breasted Barbet, etc. (14)
Blood-breasted Flowerpecker
Blue-breasted Bee-eater, etc. (6)
Brassy-breasted Tanager
Brown-breasted Bamboo-Tyrant, etc. (5)
Buff-breasted Babbler, etc. (10)
Chestnut-breasted Bunting, etc. (11)
Cinereous-breasted Wren
Cinnamon-breasted bunting & tody-flycatcher (2)
Claret-breasted Fruit-Dove
Cream-breasted Fruit-Dove
Creamy-breasted Canastero
Crimson-breasted Flowerpecker, etc. (3)
Dark-breasted rosefinch & spinetail (2)
Drab-breasted Bamboo-Tyrant
Fawn-breasted Bowerbird, etc. (7)
Fiery-breasted Bushshrike
Fire-breasted Flowerpecker
Flame-breasted Flowerpecker, etc. (3)
Freckle-breasted Thornbird
Fulvous-breasted flatbill & woodpecker (2)
Golden-breasted Bunting, etc. (5)
Gray-breasted Babbler, etc. (15)
Green-breasted Bushshrike, etc. (4)
Hairy-breasted Barbet
Ivory-breasted Pita
Lemon-breasted berrypicker & seedeater (2)
Lilac-breasted Roller
Maroon-breasted Philentoma
Ochraceous-breasted Flycatcher
Ochre-breasted Antpitta, etc. (5)
Orange-breasted Bunting, etc. (9)
Pale-breasted Illadoptis, etc. (3)
Pearl-breasted Swallow
Pearly-breasted conebill & cuckoo (2)
Pink-breasted Lark
Plain-breasted Earthcreeper, etc. (4)
Purple-breasted cotinga & sunbird (2)
Red-breasted Blackbird, etc. (15)
Rose-breasted chat & grosbeak (2)
Ruddy-breasted crake & seedeater (2)
Rufous-breasted Accentor, etc. (14)
Rusty-breasted Antpitta, etc. (3)
Saffron-breasted Redstart
Scallop-breasted Antpitta
Scaly-breasted Bulbul, etc. (9)
Scarlet-breasted Dacnis, etc. (4)
Silver-breasted Broadbill
Slaty-breasted Rail, etc. (3)
Speckle-breasted Antpitta, etc. (3)
Spot-breasted Antvireo, etc. (12)
Streak-breasted Bulbul, etc. (5)
Streaky-breasted Fantail, etc. (3)
Stripe-breasted Rhabdomis, etc. (5)
Sulphur-breasted bushshrike & warbler (2)
Tawny-breasted Flycatcher, etc. (5)
Vinous-breasted Starling
Violet-breasted Sunbird
Wavy-breasted Parakeet
White-breasted Antbird, etc. (18)
Yellow-breasted Antpitta, etc. (20)
Yellowish-breasted Racquet-tail

Okay, so maybe I lied about size and shape. Only among breeders of domestic poultry and female Greater Sage-Grouse (Centrocercus urophasianus) does there seem to be a preference for big-breasted birds; in the case of sage-grouse, the males have developed an elaborate courtship display that exaggerates the size of the breast by expansion of large esophageal pouches and partial extension of cervical apteria (i.e., unfeathered areas between feather tracts), with larger-breasted males attracting and mating with more females.

And further, who among us has never typed Double-crested Cormorant only to have it come out Double-breasted Cormorant? It happens to me all the time! And who else but birders could report back excitedly to friends and acquaintances of the opposite sex about having seen boobies and tits without blushing?