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CHAPTER 15 – NESTS AND INCUBATION AND CHAPTER 16 – PARENTS AND OFFSPRING April 17 th , going outside for lab so no lecture that morning. THINGS DUE FOR LAB PROJECT April 17 th – quite a bit going on here We will not have lecture, we’re outside for lab By 5pm on the 17 th I need from you: A Results section that tells me just what you’ve found and give statistical results 3 potential talking points for your Discussion These do not have to be fully fleshed out paragraphs, just general ideas that you believe you’d like to talk about An updated Introduction – incorporate suggestions that I gave you earlier An updated Methods – incorporate suggestions that I gave you, and you will incorporate statistical analyses statements that I will help you with NESTS, INCUBATION, AND OFFSPRING Nest construction very varied Nest location, camouflaging, & materials all influence success of nesting attempt Behavior of parents around the nest important too Colony – mobbing potential by parents and neighbors Solitary – inconspicuous behavior key Defense of the nest from predators and parasites Some methods of building are quite complex! Northern Cardinal (Cardinalis cardinalis) nestlings (24hrs old) NESTS, INCUBATION, AND OFFSPRING Nest cleanliness Nests can get pretty funky Feces can accumulate Parents typically defecate away from nest Young produce fecal sacs (at right) Molds from vegetation Parasites Ectoparasites on offspring can be damaging Some species put fragrant herbs into nest to fumigate A Prothonotary Warbler (Protonotaria citrea) removes a nestling fecal sac from the nest (this may be dropped or even consumed) NESTS, INCUBATION, AND OFFSPRING Once nest built, eggs fertilized and laid into nest, incubation begins Almost all species incubate (nest parasites, brush turkey – the exceptions) Incubation provides protection (parent is shielding eggs completely) and more importantly – HEAT Eggs need to be kept a relatively constant, high temperature to facilitate development and survival White-eyed Vireo (Vireo griseus) incubating eggs NESTS, INCUBATION, AND OFFSPRING Prolactin induces incubation behavior (and physical alterations for incubation) in both sexes. In females elevated prolactin leads to arrest in ovarian follicle development NESTS, INCUBATION, AND OFFSPRING Eggs must be continually attended Males of some species do incubate, Emperor Penguins (Aptenodytes fosteri) are some of the most famous Cooling will slow embryonic growth Delays hatching Extreme cooling will kill embryo No adult attendance – chances of parasitism or predation increase Fine balance, because for some too much parental activity – predation increases NESTS, INCUBATION, AND OFFSPRING Northern Cardinal (Cardinalis cardinalis) mate feeding In many species where males do not incubate males do bring incubating mates food (may be at the nest or away from it). Reduces female time away from nest. A male Red-tailed Hawk (Buteo jamaicensis) bringing in food. The male is ‘Pale Male’ a New York City celebrity (of sorts). NESTS, INCUBATION, AND OFFSPRING Incubation period Varies with species, can be 10-90days Physically larger species – longer Physically smaller species – shorter Adult life span, development at hatching, and predation also influential Hatching can be synchronous or asynchronous Depends on when incubation begins Drastically different outcomes based on whether all hatch together or not White-eyed Vireo (Vireo griseus) eggs, both sexes incubate 14-15d NESTS, INCUBATION, AND OFFSPRING There are 42 stages of development, and they are by and large similar across species. As development proceeds developing embryos require more energy, here the yolk is drawn from more extensively. NESTS, INCUBATION, AND OFFSPRING Developmental activities and time in early stages doesn’t vary much across species. Later stages will differ and this is important to species morphology, etc. Barred Buttonquail (Turnix suscitator rostrata) NESTS, INCUBATION, AND OFFSPRING In order to more efficiently transfer heat incubating birds develop a brood patch De-feathered skin that becomes baggy and fluid filled Hormones facilitate this development Various brood patches observed in birds Prolactin, and estrogen which induces nesting behavior and stops ovulation has many jobs NESTS, INCUBATION, AND OFFSPRING Parents can keep eggs at fairly constant temperatures Persistent attendance is needed, particularly when it is cooler NESTS, INCUBATION, AND OFFSPRING Incubation behavior does impact hatching success, and this can have surprising outcomes. At left, incubation behavior in two species introduced to Vancouver Island, British Columbia NESTS, INCUBATION, AND OFFSPRING On the other end of the spectrum, eggs can get too hot Parents provide shade, add water, or remove heat through circulation, change nest architecture Parents also turn eggs Most species this is needed for proper embryonic development Note, in reptiles (avian relatives) this will kill the embryo A Great Egret (Ardea alba) shades its nest, don’t want eggs getting too warm or too cold! NESTS, INCUBATION, AND OFFSPRING Getting out of the egg is quite a chore! Parents may help, but adaptations in embryo important here NESTS, INCUBATION, AND OFFSPRING Once egg hatches offspring care begins One or both parents will care for nestlings and fledglings Terms precocial and altricial refer to (extreme) states of development at hatching, but there are steps in between NESTS, INCUBATION, AND OFFSPRING See a gradation of possible levels of development at hatching. NESTS, INCUBATION, AND OFFSPRING Offspring development can impact breeding systems and later behavior of adults Precocial often seen in uniparental species Precocial development evolutionarily basal Other types of development evolved from this Differences exist not only in developmental state but in post-hatc hing development as well Wood Thrush (Hylocichla mustelina) trying to brood older nestlings, one is not having any of this noise (“food NOW”) NESTS, INCUBATION, AND OFFSPRING Variation in whether energy is put into growth or maturation of tissue varies with development type Can even impact full brain development and size of brain at maturity (altricial birds have relatively larger brains) NESTS, INCUBATION, AND OFFSPRING Birds are homeothermic Maintain a constant temperature different from environment At hatching homeothermy initiates Metabolism & temperature altered Differences in precocial checks and altricial nestlings Altricial not good at keeping warm NESTS, INCUBATION, AND OFFSPRING In both species young individuals get to a point where they maintain adult body temperature, but precocial get to it earlier and are better at sticking at that temperature when young. NESTS, INCUBATION, AND OFFSPRING Energy use by nestlings is enormous Growth, maturation of tissue, temperature regulation Nutrition important too Lipids and carbohydrates – high energy molecules Proteins – lean tissues (organs), muscles, feathers Calcium – bone growth Worst thing I’ve seen young Blue Jay (Cyanocitta cristata) parents feeding offspring cracked corn NESTS, INCUBATION, AND OFFSPRING NESTS, INCUBATION, AND OFFSPRING To stimulate parents to bring food nestlings beg Calls Frantic waving and swinging of the body Vividly colored mouth linings Downside is that predators can hear this too NESTS, INCUBATION, AND OFFSPRING NESTS, INCUBATION, AND OFFSPRING Typically there are more than one offspring in a nest Age and size may differ Will lead to competitive differences for food Bigger/older dominant Asynchronous hatching First hatched larger than last hatched Maternal effects Better provisioned eggs = better babies Here young Laughing Kookaburra (Dacelo novaeguineae) fight to establish dominance and prime positions in the nest burrow. If interested in this topic read Doug Mock’s: More Than Kin and Less Than Kind NESTS, INCUBATION, AND OFFSPRING Extreme form of rivalry is siblicide Common in eagles (some), skuas, herons, boobies Larger, older, dominant chick kills the other Pecking it to death, pushing it from nest Nazca Boobies (Sula granti) regularly have siblicide occurring in their nests Why? Parents unable to raise more than 1 Insurance if egg 1 infertile NESTS, INCUBATION, AND OFFSPRING Nestlings need lots of attention – this is expensive for parents Getting lots of food, stuck at the nest brooding Parents also need to take care of themselves Conflict! What do you do? Pick and c hoose who gets your attention Promote the dominant ones, alter sex ratio, allow siblicide Prefer your survival over offspring survival Get helpers Make sure your mate pulls some of the load Alter hatc hing sequence or alter egg components (female tactics) Hatching, and hence size, asynchrony in Ospreys (Pandion haliaetus). Oldest/biggest is on left, youngest/smallest tucked in at right NESTS, INCUBATION, AND OFFSPRING How you have to work can impact your survival, and what’s good for a female isn’t always what works for a male. NESTS, INCUBATION, AND OFFSPRING Nestlings grow and mature and eventually leave the nest – now are fledglings Parents still have to assist fledglings Precocial – may not be much, just directing or guarding Altricial – can still be substantial amount of work Fledglings are not the most coordinated High mortality due to predators High mortality due to starvation Fledgling Dark-eyed Junco (Junco hyemalis) NESTS, INCUBATION, AND OFFSPRING Nestlings and fledglings need to learn as well as grow Neurological development proceeds during growth, associations are made Young birds learn to avoid predators, have innate fears Imprinting Critical learning periods where an indelible impression about something is made May imprint on a parent, on a foraging method, on a predator, or on your species (sexual recognition) NESTS, INCUBATION, AND OFFSPRING Here the imprinting has led the geese to see humans as mates Here the baby geese see Lorenz as ‘mama’ Konrad Lorenz studied imprinting behavior in geese as well as other innate behaviors in birds NESTS, INCUBATION, AND OFFSPRING The Village Indigobird (Vidua chalybeata) is a nest parasite – it imprints on the host species vocalizations The Brown-headed Cowbird (Molothrus ater) is a nest parasite – it doesn’t imprint on the host species vocalizations NESTS, INCUBATION, AND OFFSPRING Young birds have lots to learn! May need to learn migration routes May need to learn how to hunt/forage May need to learn predators May need to learn songs May need to learn how to interact socially with others Fledgling American Robin (Turdus migratorius)