Chapter 9: Annual Cycles Flashcards
Breeding cycles driven by? (x4)
availability of food, nest sites, locations of favorable climates, and times of low predation risk
released from pituitary, normal posthatching growth, fat metabolism and synthesis, stimulates immunie system
Growth hormone (GH) (x4)
begin annual cycle at sight of green pine cones
pinon jays
rainfall
key timing variable in equatorial places (heavy rain stimulates gonzad size increase b/c increased food availability)
migratory restlessness
zugunruhe
kingfishers
peak at the end of the dry season when streams are clear and fish can be easily seen
clocks that regulate 24-hour cycles; tied to earth’s rotation on its axis
circadian rhythms (x2)
longer (6-12 months) vs shorter (_>_4 months)
tropical vs temperate climates
estrogen (x4)
migratory restlessness, progesterone release by pituitary gland, egg production in oviduct, secondary sexual morphology and brain function
released from pituitary gland, produces crop milk in pigeons, incubation behavior and broodiness, photorefractoriness of testes
prolactin (x4)
early spring restlessness, triggered by increased day length
also triggers?
hyperphagia (x2)
fat deposition
seasonal nesting patterns at northern sites but prolonged breeding at tropical sites
low water temperatures (depresses food availability) delay breeding
hurricanes cause irregular breeding (in Caribbean and parts of South America)
brown pelicans (x3)
2 pituitary hormones
- stimulates testosterone release in testes in males; ovulation, progersterone and testosterone production in females
- stimulates sperm production in males (testes) and egg follicle development in females (ovary)
- luteinizing hormone (LH)
- function? - follicle-stimulating hormone (FSH)
- function?
brown pelicans (x3)
seasonal nesting patterns at northern sites but prolonged breeding at tropical sites
low water temperatures (depresses food availability) delay breeding
hurricanes cause irregular breeding (in Caribbean and parts of South America)
daylight
diurnal
activates annual cycle stages by stimulating internal (hormonal) response
i.e.?
environmental cures
i.e. white-crowned sparrow (molt, autumnal migration, overwintering, vernal migration, breeding)
permanent residents
breed, molt, and survive until next breeding season
e.g.?
simplest annual cycles; birds who live in same place year-round
birds must…? (x3)
e.g. rock pigeon
luteinizing hormone releasing hormone (LHRH) (x2)
released from hypothalamus, produced LH and FSH by pituitary gland
extrinsic migration timing factors (x3)
temperature, barometric pressure, wind
emlen (1969) w/ indigo buntings
cause to molt an extra time during the year by increasing the photoperiod
temperature & water availability
others?
2 key variables of gonadal cycle (change during annual cycle)
-social stimulation (displays), presence of certain foods, growth of new vegetation
circannual cycles (x2)
controlled by 2-part system?
clocks that regulate annual cycles; tied to earth’s rotation around the sun
- internal circadian clocks (track day length)
- environmental light cycles stimulate neural receptors
control annual cycles as well; have a period of about 1 year
e.g.?
endogenous rhythms
starling experiment: 12/12 light/dark cycle, still came into breeding at predictable times
cause to molt an extra time during the year by increasing the photoperiod
emlen (1969) w/ indigo buntings
migratory restlessness, progesterone release by pituitary gland, egg production in oviduct, secondary sexual morphology and brain function
estrogen (x4)
glucagon (specics x4) & corticosterone
released at end of breeding season (with thyoxin) to stimulate fat deposition (for migration)
-from pancreas, metabolism in liver and muscles, release of fatty acids to blood plasma, & fasting
environmental cures
i.e. white-crowned sparrow (molt, autumnal migration, overwintering, vernal migration, breeding)
activates annual cycle stages by stimulating internal (hormonal) response
i.e.?
availability of food, nest sites, locations of favorable climates, and times of low predation risk
Breeding cycles driven by? (x4)