• Shape 
• Habitat
• Behavior
• Range
• Field marks
• Sounds

• Contour
• Bristle
• Filoplume
• Semiplume
• Vaned flight
• Down

3 major pigments include

• Melanin- Earth tones: grays, blacks, borwns, buffs. More melanin = extra keratin = increases feather strength (black wing tips of aerial species)
• Carotenoids- Bright reds, oranges, yellows, some purples and some UV. This is diet dependent. Typically found in back and brest feathers
• Porphyrins- browns, reddish-brown, magenta, green. Fluoresce bright red when exposed to UV light.

• Capital (head)
• Humeral (upper wing)
• Alar (trailing edge of wing)
• Ventral (belly/brest)
• Spinal
• Femoral (butt)
• Crural (leg)
• Caudal (tail)

replacement of old feathers with new ones.

•  Seasonal occurance

set of feathers present after a molt

1. Fusion if bones
2. Reduction and residtribution of mass
3. Specific modifications

• thoracic vertebrae
• pelvic bones
• avian "hand" (carpometacarpus)

• Lack of teeth and heavy jaw bones
• Pneumatic (hallow and filled with air spaces)

• Large keel on sternum- attachment point for muscles responsible for flight
• Furcula (wishbone) and coracoid- furcula allows flex during flight. Coracoid bones brace thorax against force of flight

Synsacrum

function