Avian Bio feathers continued

Plumage

The collective layer of feathers covering a bird, varying by species, age, gender, and season in color, pattern, and arrangement

Molting process

Shedding and replacing feathers between age classes and annually. Can happen gradually or all at once, tend to molt feathers on the inside and work outward.

Subadult vs. Adult

Subadult: Juvenal plumage (comes before adult)

Adult: definitive plumage

Annual cycle molting process: Basic plumage vs. alternate plumage

The bird skips a distinct "formative" plumage phase after its juvenile feathers, moving directly into adult-style cycles

Basic: non-breeding or winter plumage

Alternate: during the spring and summer, traditionally called breeding plumage

Annual cycle molting process: Complex vs. Simple

The young bird sheds its initial juvenile plumage into a distinct formative plumage during its first year via a partial preformative molt.

Complex: The bird undergoes a preformative molt before entering its definitive basic cycle. (additional plumage)

Simple: no additional plumage

Annual cycle molting process: terminology

Juvenal plumages —(pre-basic)—> Basic plumage —(pre-alternative)—→ alternative

Feather care: Preening

Feather maintenance- soothing out barbs of feathers (removing debris/oils/ectoparasites)

Feather care: Uropygial gland

Oil gland at base of tail (feather conditioner)

Produces an oily secretion that birds collect with their beaks and spread over their feathers during preening

Visible spectrum of birds

Birds eyes are sensitive to a greater portion of electromagnetic spectrum (can see longer/shorter wavelengths like UV light)

Hue

“color”

Saturation

Purity of hue

Intensity

brightness (how much color)

Pigmentary color

Comes from specialized chemical molecules inside feathers, skin, and eyes that absorb certain wavelengths of light and reflect others

Pigmentary color: Melanins

Synthesized by amino acids → made by the bird

(mostly earth tones)

Pigmentary color: Eumelanins

black/grey

Pigmentary color: Phaeomelanins

redish/brown

Carotenoids

• brighter colors (red/oranges/yellows)

• consists of large carbon chains that re-emit light

• not synthesized in the body like melanins, OBTAINED FROM DIET (ex. Flamingo)

Coloration: Porphyrins

• consists of modified amino acids made by birds

• purples/reds/greens

• birds see these colors much different

Incoherent light scattering

Produces a white light (white bird) due to the randomness of air bubbles in the feather barb. Light bounces off every direction at different times, mix of all colors = white.

Coherent light scattering

Produces vibrant, non-shifting blues due to a specific pattern of air bubbles of the melanin that reinforces certain wavelenghts.

Structural blues

Air bubbles in keratin matrix are arranged in a specific way that scatter in short waves (blues).

Iridescence

When the hue observed shifts depending on the viewing angle. The effect is produced inside the barbule by combos of air, melanin, and keratin.

Crypsis coloration

Camouflage to blend in with the background (ex. Potoo) color and behavior.

Disruptive coloration

Camouflage: pattern of the animal breaks up and distracts from the actual shape of the bird (ex. neck band of the plover)

Countershading coloration

Camouflage where the bird is darker on the top, lighter on the bottom (typical of open country and water birds”

Social recognition and signaling

Sexual Dichromatism (male vs. female coloration) and age recognition (female choosing adult amek instead of a child male)

Sound production: The wings of a manakin & the tail of the hummingbird

Knock wings together causing clubbed shaped secondaries to vibrate producing a “ting” sound for courtship.

Sound production: The wings of a manakin & the tail of the hummingbird

Club wings, stridulation: tooth + comb to make a loud sound. Comb = feather 6 that has ridges. Tooth = feather 5 that has a bent rachis.

Sound production: The wings of a manakin & the tail of the hummingbird

Different species have different shaped tails, which means they produce different sounds. The shape of the tail determines the sound, and the closeness of tail feathers also determines the amplification. J-shaped dive display causes “tail chirp”.