Avian Natural History

a)feathers b)oviparous c)endothermic d)flight (not ratites, penguins, island birds) e)bipedal (with wings) f)beak g)small size (no more than 150 kg)

a)feather morphology b)nesting habits c)environment selection d, e) locomotory speed/lift f) foraging mode g) body size (2 g – 150 g)

-tracts of dead keratinized tissue (homologous with lepidosaur scales) - all have calamus, rachis, and vane (containing barbs and barbules) - flight and tail feathers long and asymmetric (optimize for displacing air) - downy feathers plumbaceous (insulation) - many brilliantly colored regions, often in males, used in mate attraction or rival deterrence

(a)lightened: hollow bone, feathers, no bladder, 1 ovary - except diving ducks (need to sink) (b)large flight muscles: pectoralis major & supracoracoideus - can account for 30-60% of all body muscle! - leg muscles enlarged in predatory raptors (c)superior respiratory performance: large heart, high BP, air sacs
(d)protractable streamlined skeleton (e)myoglobin (oxygen-binding protein) enrichment in aerobic muscles - “dark meat” of chicken/turkey
(f)wings are airfoils and propellers (can change angle of attack) - area varies according to mass of bird (wing loading) - pectoralis major powers downstroke; supracoracoideus powers upstroke

Hindlimbs!!

Webbed/lobed feet (ducks)*paddling

- insect = short/thin (warblers) - vertebrate = heavy, hooked (hawks/gulls) - plankton = long, filtering (duck, flamingo) - seeds = short, stout, even curved (finches, parrots) - hole-probing = long/thin (reach; hummingbirds) stout (drilling) (woodpeckers) tongues acquires/manipulates food too

Gull (heavy, hooked)

-large eyes, optic lobes, and midbrain - locate prey + avoid being eaten - see UV light (feather color + food)

- roughly equal to human range - large tympanic membrane to enhance sensitivity - esp. sensitive in owls (nocturnal hunters) - facial ruff is parabolic sound reflector - songbirds tuned to high frequency (song) as well some tuned to low freq. too (approaching thunder)

- some with v. small olfactory bulbs (poor smell) - water, ground, and hunting birds have larger bulbs (find food or escape predation) - may play a role in navigation (homing) - tangerine scent of crested auklets is used in mating

- air pressure (flight, weather patterns) - magnetic fields (orientation; magnetite found in heads of pigeons)

(a)Rapid act = “cloacal kiss”
(b)Much higher investment in mate competitions - colors and patterns - behavioral displays - song*these features also play a role in species recognition

-males want multiple mates (sperm is cheap), females want one (help raising young)
- polygamy occurs in birds (more common in mammals): polygyny (polyandry rare) - social monogamy is most common though (90%; high parental investment by fathers)
- pair bonds are typically annual; lifetime monogamy almost non-existent
- extra-pair copulations (typically covert) also are frequent (0-60%) * males inseminate more mates * females get a better genetic mate * females get different/diverse genes

- eggs produced in clutches (1 every few years to 25 per bout, up to 3 bouts)
- nests can include classic cup nest, tree cavity, on rocks, in burrow * covered in megapodes, on feet of penguins* some colonially (gulls) - mothers (typically) incubate by sitting on eggs (exposing brood patch)
- sex determined by genes, sex can be biased according to diet/mate

- some young hatch mature (precocial), typically ancestral birds (ducks, gamebirds) * require little attention
- others hatch naked and immature (altricial); a derived trait * require warmth, food, and predator protection - some stay with parents for days (10-12); others remain for years * cooperative breeding (kids help parents breed)