A male House Sparrow develops a larger black bib as it matures and this acts as a clear signal to junior males as to their position in a pecking order

---

A male House Sparrow develops a larger black bib as it matures and this acts as a clear signal to junior males as to their position in the pecking order, important in a rigid social order

---

Size: 3853px × 4600px
Location: Scarborough, UK
Photo credit: © Nick Greaves / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: -adult, -operative, 4, aerodynamics, aves, behaviour, bib, bird, birdlife, birdwatching, blooded, breeder, chambered, contour, crab, dimorphism, dinosaur, diurnal, domesticus, dominance, extended, family, feathers, feeder, flocks, foraging, granivore, gregarious, ground, heart, helpers, hop, house, keratin, living, monogamous, nest, noisy, olfactory, oscines, passer, passeridae, passerine, plumage, pots, preening, primary, regional, scales, secondary, sexual, sleeps, social, sparrow, sunbathing, untidy, variation, vertebrate, warm, woodlands, woven