Transcript Chapter 15 – nests and incubation and chapter 16 – parents and

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)