Ornithology

Appearance

Physiology

Behavior

Reproduction

Molt

Migration

Overwintering →

Vernal migration →

Breeding →

Molt →

Autumnal migration →

Overwintering

Breeding = mate in breeding condition, plenty of food

Molting = No mate (or not in condition), not enough food, young independent

Cycle matches the availability of food

Breeding/parental care occur throughout high food availability

Molting/dispersal occur when the availability of food decreases

Biological clock & general patterns

Photoperiod & social cues

Environmental & social cues

Constant dim light = shift to a 23 hr cycle by chaffinches unless stimulated by 24-hr cycle

Longer day lengths = ↑ size of testes in juncos

Kingfisher - low water during summer--late hatch

Rufous collared sparrow - lives in tropics; 2 breeding seasons/yr based on wet/dry patterns

Sooty tern - 2 breeding seasons/yr, but only for birds that failed first breeding season

Day length

Temperature

Food

Habitat

Avoid seasons and areas w/ ↓ resources

Capitalize on ↑ resource rich areas and seasons

• Sun-Azimuth: orient with sun, change hourly
• Skylight polarization: indicates sunset
• Star Compass: restlessness, orientation
• East-West Time Shifts: change in sunrise time
• Magnetic Compass: use Earth's m-field

• Gender
• Leapfrog Effect
• Timing
• Type of Flight
• Altitude (Songbirds < 5000 ft, most below 2500 ft; Waterfowl and shorebirds 10,000-20,000 ft.)
• Fat reserves

Experience + orientation ability

Geographic features

Local & broad scale

• Pacific
• Central
• Mississippi
• Atlantic

• Respond to longer days and warmer temperatures
• Long distances, fast northward push, may not wait for favorable weather
• Males typically come first
• ‘Reverse migrations’ common
• Smaller in scale due to winter mortality

• Respond to shorter days and wintery weather, cold clear nights
• Protracted - long stopovers
• Birds in no hurry, more likely to wait for favorable conditions
• Larger in volume due to young of the year

• Flyways - ducks, shorebirds
• Leading lines - raptors

• Seasonal and meteorological forces 
• Downed grebes in parking lots

• Bottom line: pass your genes on
• 2 ways: mating; kin selection

• Good Genes (Handicap, Male health)
• Arbitrary choice (Runaway selection)

Female kiwis = large eggs proportional to body size

• 92% of birds
• Male help necessary for raising young
• Males cannot monopolize resources for extra mates

• 2% of birds
• Parental care by female
• Patchy environments
• Young often precocial

• <1% of birds
• Gruiformes & Charadriiformes
• Males incubate and care for young

• 6% of birds
• Indiscriminate sexual relations

• Ruffs
• “Faeders” - combine feminine and masculine behaviors
• Testes 2.5 x the size of normal males

• 0-50% of young are from EPCs
• 10-25% of songbirds

• Males - increase fitness, future mates, fertility insurance
• Females - fertility insurance, genetic diversity, resource access

Protection from predators and elements

• Vary, but most are from 2-4 eggs
• Eggs are costly to produce and care for

• Shell: protection, gas exchange 
• Shell membranes: bacteria shield, prevent dessication
• Albumen: shock absorber
• Yolk: energy supply

• Crypsis
• Biliverdin in females = blue color
• ↑ blue = ↑ provisioning rates

• Common in ducks
• Common goldeneye: mean r = 0.13 (first cousins)

• Independently evolved ≥ 7 times
• > 90 species (cowbirds, cuckoos)

• Egg mimicry
• Hard-shelled eggs
• Relatively small eggs
• Disposal of eggs
• Mafia hypothesis

Group of interbreeding species that live in the same area and have normal patterns of migration and dispersal

Birth + immigration = ↑ pop. size

Death + emigration = ↓ pop. size

• λ = (1 + births + immigration - deaths - emigration)
• Geometric growth (or decline) of a population over a finite time interval

Quantitative generalizations of nature

Coexisting groups of species

• Most species are rare
• Few are abundant

• Niche: ecologically similar species have non-overlapping niches
• Nuetral: ecologically similar species have overlapping niches

Species richness is a function of "island" area and distance from "mainland"

Extinction rate ↑ over last 400 yrs

5 mass extinctions

Currently in 6th mass extinction event

• Extinct: 131 species (mostly islands)
• Endangered: 532 species
• Vulnerable: 674 species

• Declining: 208 species
• Increasing: 118 species
• Stable: 88 species
• Grasslands (short grass prairie) are threatened

• Heath hen
• Dodo
• Great auk
• Carolina parakeet
• Labrador duck
• Passenger pigeon

• Bald eagle
• Peregrine falcon
• Wood duck
• Wild turkey
• Whooping crane
• California condor

The single most important factor in managing and conserving birds

• Brood parasitism
• Habitat destruction
• Feral cats

• Juveniles tend to migrate sooner than adults
• Individuals lose a lot of mass during migration
• During staging, they accumulate fat stores up to 46% of body mass
• Muscle atrophy ~11%
• ↑ fat = postponing migration for ↑ darkness (winter months) when ↓ predation risk

• Instead of viviparity, birds have adapted to reproduce successfully
• The costs of oviparity outweigh the costs of vivparity

• The gizzard of the phainopepla can remove the exocarp from mistletoe seeds
• By not grinding the seeds, the bird can save time and energy digesting and can plant whole seeds for the plant

• Hippocampus = memory section of brain
• Chickadees cache food for winter
• Take-home: # of hippocamopal neurons of chickadees is greater in areas w/ more severe winters