midterm 3 Flashcards
What are the bird chromosomes?
Males ZZ, females ZW
Explain copulation
Called - cloacal kiss
- a few seconds to half an hour
- high frequency - 500 - 600 times per clutch laid (because success rate may not be high)
- sperm concentrations are high
- some species have penis like organs - waterfowl, game birds, ostritch
What is sperm competition? Why is there advantage to females in sperm competition
Multiple males will mate with the same female - best or most well timed sperm will win
- means that medium to high quality females will get high quality mates
- males compete for females
Advantages and costs to sperm competition in males
- super energy costs for mating rituals
- beneficial if you are high quality, easy to mate
General facts about egg laying
- lay eggs in the morning
- laying interval - dependent on energy it takes to produce
- 1 per day in passerines
- 1 every other day for larger birds
- big birds up to 4-5 days
- lay until clutch is complete
What determines a clutch being complete?
- clutch is complete when it is no longer energetically feasable to lay more eggs
- determinate layers by set numbre of follicles that develop
- inderminate layers have an unlimited number of follicles develop if eggs are removed they will continue laying
what is oology?
the study of eggs
What kind of birds do not lose feathers / form true brood patches?
waterfowl, pelicans - require down for waterproofing and warmth - will get wet and cold if featherless
Why does incubation only begin at the last egg laid?
If hatching is not synchronized - babies hatching at all different times, different life stages, chaos
increased level of attentiveness improves what?
hatching success rate - but variable between species
What part of the egg keeps the embryo stuck in position?
chalaza
Costs of incubation?
16-25% of daily energy
- nest insulation / finding or creating favorable microclimate
- sedentary - predation risk
- reduced foraging time - fasting, male provisioning, may have to trade off incubation vs starvation
Go catchup on allllllllllllllllllllllllll the slides
ok
Ritualized behaviours
- evolution of signals and displays from non signal movements
- headthrows in the goldeneye
- used to attract mates or to strengthen pair bond after mate choice has occurred
- April - may
Types of courtship displays
Song
Dance - flight or posture
Feeding activities - courtship feeding
Nest building
Bower building
What is the ultimate goal of courtship displays?
Reproduction!!
What is avian demography
Demography involved population fluctuations
- balance between survival and reproduction
- population level - fitness is individual level
-reproductive rates somewhat easier to measure through fledging but difficult afte that
- first year dispersal patterns affect both survival and reproductive success
- true especially for passerines - they are short lived and hard to find and dont have great site fidelty
- less true for longer lived birds that have a higher recapture rate and more site fidelity
3 things about avian survival rates - which zone is best?
- ideally done using capture / recapture models like MARK or R
- dogma says tropical survival is greater than migrant survival is greater than temperate resident survival
- differences between regions not as dreastic as suggested by early literature
- its not that simple
Main difference between tropics and temperate zonez
Tropics poor nutrients but can exist year round
Reproductive options - variables
- age at first reproduciton - usually annual cycles but longer for big birds
- egg size - can be demanding
- clutch size - demanding
- number of brood in a breeding season
What are years where birds of reproductive age elect not to reproduce
sabbatical years
What limits the number of broods in a breeding season
energy / life history
Two types of population regulation
Density dependent - social factors are at work - real answer but variable
Density independent - climatic factors main control
usually a mixture as all populations are density dependent
How many eggs per clutch? Same species / same climate
Tropical house wren - 2-3 eggs
Temperate house wren - 7 eggs
Arctic ducks - 10 eggs
Arctic seabirds - 1 egg
- provisioning - less eggs but more resources
Why is clutch size less than physiological maximum
because if you put yourself on deaths door you risk not being able to raise young or breed in the future
Mortality and reproduction - comparision
- shorter lived higher mortality species with more young
- longer lived lower mortality species with fewer young
Why not raise one large baby?
because neighbors that have more will have an overall higher reproductive success
What determines the optimal clutch size
the size that produces the survival of the most young
what egg do many birds begin incubation with?
penultimate - second last - egg, they often dont wait until all eggs are laid
- causes hatching asynchrony - may remove resources from youngest chick if scarce
Three types of hatching synchrony
- full synchrony
- hatching asynchrony
- partial asynchrony
- size and type of brood depend
High synchrony
All eggs hatch at same time
- makes sense in precocial young because they move after birth
- waterfowl and galliformes
Hatching asynchrony
- bet hedging / good years
- chicks reared = available resources
- often have an insurance egg
Partial asynchrony
- many altrical birds
- incubate next to last egg
Does brood reduction happen post fledging?
- in sepceis with high parental care may split brood among parents
- if food is scace may mix smallest and largest young within each group
- if food is plentiful, make group of smallest and group of largest
Intraspecific brood parasitism
- widespread
- few nest sites but high density
- reduced host productivity
- but sometimes is a matter of eggs in more than one basket
- within same species
Interspecific broot parasitism
- occurs between different species
- some species cannot recognize different species
- can be facultative or obligate
What are mimetic eggs?
some species like cuckoos can lay eggs that look similar or identical in pattern to the eggs of the host species they want to place their egg in
What fraction of birds are monogamous?
90-92% of species - seen as fit to have both parents contributing
