The flashcards below were created by user
lucashall
on FreezingBlue Flashcards.
-
What changes over annual cycles?
Appearance
Physiology
Behavior
-
3 places to put excess energy
Reproduction
Molt
Migration
-
Typical cycle of a migratory bird
Overwintering →
Vernal migration →
Breeding →
Molt →
Autumnal migration →
Overwintering
-
Typical cycle of non-migratory bird
Breeding = mate in breeding condition, plenty of food
Molting = No mate (or not in condition), not enough food, young independent
-
Typical annual cycle in the tropics
Cycle matches the availability of food
Breeding/parental care occur throughout high food availability
Molting/dispersal occur when the availability of food decreases
-
How are annual cycles regulated (set)?
Biological clock & general patterns
Photoperiod & social cues
Environmental & social cues
-
Light deprivation studies
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
-
Atypical examples of annual cycles
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
-
Origin of migration
Day length
Temperature
Food
Habitat
-
Why migrate?
Avoid seasons and areas w/ ↓ resources
Capitalize on ↑ resource rich areas and seasons
-
Types of orientation during navigation
- 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
-
Different navigation strategies
- 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
-
Navigation factors
Experience + orientation ability
Geographic features
Local & broad scale
-
Flyways & leading lines - where?
- Pacific
- Central
- Mississippi
- Atlantic
-
Spring migration - key concepts
- 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
-
Fall migration - key concepts
- 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 vs leading lines (types of birds associated with each)
- Flyways - ducks, shorebirds
- Leading lines - raptors
-
Causes and issues related to fallout
- Seasonal and meteorological forces
- Downed grebes in parking lots
-
What is the bottom line of breeding and 2 ways that it is accomplished
- Bottom line: pass your genes on
- 2 ways: mating; kin selection
-
2 hypotheses for elaborate plumage
- Good Genes (Handicap, Male health)
- Arbitrary choice (Runaway selection)
-
Differential investment in offspring (male vs female)
Female kiwis = large eggs proportional to body size
-
Monogamy
- 92% of birds
- Male help necessary for raising young
- Males cannot monopolize resources for extra mates
-
Polygyny
- 2% of birds
- Parental care by female
- Patchy environments
- Young often precocial
-
Polyandry
- <1% of birds
- Gruiformes & Charadriiformes
- Males incubate and care for young
-
Promiscuity
- 6% of birds
- Indiscriminate sexual relations
-
Odd examples of breeding
- Ruffs
- “Faeders” - combine feminine and masculine behaviors
- Testes 2.5 x the size of normal males
-
Frequency of Extra Pair Copulation (EPCs)
- 0-50% of young are from EPCs
- 10-25% of songbirds
-
Motivations for Extra Pair Copulations
- Males - increase fitness, future mates, fertility insurance
- Females - fertility insurance, genetic diversity, resource access
-
Purpose of nest
Protection from predators and elements
-
Clutch sizes
- Vary, but most are from 2-4 eggs
- Eggs are costly to produce and care for
-
-
4 main components of egg
- Shell: protection, gas exchange
- Shell membranes: bacteria shield, prevent dessication
- Albumen: shock absorber
- Yolk: energy supply
-
Why are eggs differing colors (specifically reason for bright blue color)?
- Crypsis
- Biliverdin in females = blue color
- ↑ blue = ↑ provisioning rates
-
Conspecific brood parasitism
- Common in ducks
- Common goldeneye: mean r = 0.13 (first cousins)
-
Obligate parasitism
- Independently evolved ≥ 7 times
- > 90 species (cowbirds, cuckoos)
-
Adaptations of obligate nest parasites
- Egg mimicry
- Hard-shelled eggs
- Relatively small eggs
- Disposal of eggs
- Mafia hypothesis
-
Definition of a population
Group of interbreeding species that live in the same area and have normal patterns of migration and dispersal
-
BIDE factors
Birth + immigration = ↑ pop. size
Death + emigration = ↓ pop. size
-
Lambda
- λ = (1 + births + immigration - deaths - emigration)
- Geometric growth (or decline) of a population over a finite time interval
-
What are models?
Quantitative generalizations of nature
-
Definition of a community
Coexisting groups of species
-
Rarity
- Most species are rare
- Few are abundant
-
Niche vs. Neutral theory
- Niche: ecologically similar species have non-overlapping niches
- Nuetral: ecologically similar species have overlapping niches
-
Island Biogeography
Species richness is a function of "island" area and distance from "mainland"
-
Extinction
Extinction rate ↑ over last 400 yrs
5 mass extinctions
Currently in 6th mass extinction event
-
Current conservation status of birds (i.e. extinct, threatened, etc.)
- Extinct: 131 species (mostly islands)
- Endangered: 532 species
- Vulnerable: 674 species
-
North American trends of conservation status
- Declining: 208 species
- Increasing: 118 species
- Stable: 88 species
- Grasslands (short grass prairie) are threatened
-
Conservation failures
- Heath hen
- Dodo
- Great auk
- Carolina parakeet
- Labrador duck
- Passenger pigeon
-
Conservation successes
- Bald eagle
- Peregrine falcon
- Wood duck
- Wild turkey
- Whooping crane
- California condor
-
Importance of habitat
The single most important factor in managing and conserving birds
-
Contemporary issues in conservation
- Brood parasitism
- Habitat destruction
- Feral cats
-
Readings: eared grebe migration
- 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
-
Readings: viviparous birds
- Instead of viviparity, birds have adapted to reproduce successfully
- The costs of oviparity outweigh the costs of vivparity
-
Readings: phainopepla digestion
- 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
-
Readings: chickadee memory
- 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
|
|