ADVANCED
ORNITHOLOGY
Anatomy &
Physiology
Part II
Reference Chapters 1 & 6
University of Rio Grande
Donald P. Althoff, Ph.D.
LEC
05
• Birds and
mammals
regulate their
body
temperatures
“just” below
temperatures
that destroy
body proteins.
Curved line
represents the
____________
____________
_________ Temperature of Birds
BIRDS
Higher Body Temperatures
• In frigid Arctic regions and hottest deserts, most birds
have 40oC internal body temp. Most birds ________
(~104-110oF)
• High body temp enhances intrinsic reflexes processing
powers—enable active-fast moving capabilities.
• Higher temps—higher rate of physiological processes
ex. transmission speed _____________ increase
1.8 times with every 10oC increase in temp
ex. speed and strength of _______________
_______________ triples with 10oC
increase in temp
Respiratory
Systems
NOTABLE CHARACTERISTICS
• Lungs small and compact (compared to mammals)
• Lungs are spongy structures “molded” along the ribs.
• Dense tissues of avian lungs weigh as much as lungs
of mammals of equal body weight but only occupy
about have the volume
• Healthy lungs are ___________ in color
• Healthy lungs are _______________
• AVIAN LUNGS are unique in that air flows in only
_____________ (vs. in and out for other vertebrates
Gary Ritcheson EKU
Respiratory System…con’t
• Most birds inhale air through nostrils / _______ at
the base of the bill
• For __________, a flap—or __________—covers
and protects the nostrils from water while diving.
• For ________________, the operculum is present to
keep pollen out.
• Nasal chamber “folds” –________– (see Fig. 6-3 Gill)
that increase the surface area for air to flow over:
a) _______ the air
b) _______ the air
trachea
Gill Fig 6-2 ↑
Ventral view
Doral view
Interclavicle
air sac
cervical sac
diverticulum of the
interclavicular sac to the
sternum, coracoid,
clavicle, and humerus
mesobranchi
mesobranchi
anterior thoracic air
sac
recurrent bronchi
posterior thoracic air sac
opening of
mesobranchi
into the air sacs
abdomenal air sac
cervical
sac
Diagram of the lungs and air sacs of the bird.
parabronchi
dorsobronchi
Ventral view on left, dorsal view on the right.
Inspiration part of system shown in “black”; expiration part of system shown in “stipple” pattern.
Source: Pettengill (1985) Fig. 22, page 74.
Internal structure of bird lung
Interconnecting Bronchial Tubules—
secondary
bronchi
primary
bronchi
Gill Fig 6-4a
tertiary
bronchi
(parabronchi)
connections
to air sac
Closer look—lung tissue
Gill Fig 6-4b
• Tertiary bronchi
(i.e., parabronchi)
and fine air
capillaries
constitute most of
lung tissue--
Cycle 1
____-directional movement of a single
1
2
3
4
Inhaled volume of air—shown in white
inspiration
expiration
Cycle 2
inspiration
expiration
Gill Fig 6-5
_______________
respiratory cycles
(inspiration,
expiration,
inspiration and
expiration) are
required to move
the gas through its
complete path.
Cycle 1
UNI-directional …con’t
Cycle 2
This “design” ____________
contact of fresh air with
respiratory surfaces of the
lungs.
And…most importantly
allows a bird to replace
nearly _________ in its lungs
with each breath
This “design” makes for a
________________ of gas
exchange than do mammals
Gill Fig 6-5
Respiratory System…AIR SACS
• Although inconspicuous, the air-sac system is integral
part of the avian respiratory system.
• Number of air sacs varies from 6 in weavers, to 7 in
loons and turkeys, to at least 12 in shorebirds and
storks. Most birds _______.
• The paired cervical sacs located in the neck are
perhaps the most visible: they inflate as large red
sacs on the necks of displaying frigatebird and
strutting sage grouse
Respiratory System…AIR SACS…con’t
• ____________ (only 1-2 cell layers thick)
• Extend throughout body cavity AND into wing and
leg bones
• Connect directly to primary and secondary bronchi
• Help continuous unidirectional flow of air through
lungs…facilitating ____ transport
• Help remove potentially lethal _________ generated
during flight
• Air pressure from the single interclavicular sacs is
essential for _________ production (more about that
when vocalizations are covered).
Respiratory System…con’t
• During flight:
expansion and contractions of the ________
complement the movements of the sternum…
this helps pump air through the respiratory
system.
• High speed video of common starlings shows:
furcula bends ________ during wings’ downstroke
and then ___________ on upstroke….the
expansion is almost ______ more than in resting
width…and does so with each wing beat!
• Rate of breathing varies by species—including by size
of bird & by activity. Resting 2-g hummingbird -143
bpm; resting 10-kg turkey breathe – 7 bpm. Increase
rate by ___________________!
Digestive Systems
NOTABLE CHARACTERISTICS
• _____________
• Bill and mouth primary function is _____________ (vs.
some “mastication”)
• Bill/mouth for some capable of cracking and shucking
seeds or tearing prey into bite-size pieces
• Crop—for some—is temp food storage
• __________: size and degree of presence varies by
species…and that is associated largely with diet. A
substitute for teeth.
• GI-tract size and structure can vary seasonally
• Have ______ taste buds and _______ saliva
• _________ digestion begins in the ________________
Digestive Systems
NOTABLE CHARACTERISTICS… ____________
• Very muscular structure
• Lined with lubricating __________ glands
• For large prey swallowed whole, it _________ greatly
(think pelicans!)
• In pigeons, it produces what is know as “_________”
for young
• In pigeons and other species, it can be ________ for
display and sound resonance
• The “crop” is a __________ of the esophagus
Digestive System
MAIN TRACT
•
•
•
•
•
•
•
•
•
•
Oral cavity
Pharynx
Esophagus
Crop (*)
Proventriculus
Gizzard
Small intestine
Large intestine
Cecum
Cloaca
AUXILLARY
• Liver
• Pancreas
Don’t forget the Hoatzin…
modified CROP allows
“ruminant-like” digestion
Earthworm
small intestine
anus
mouth
pharynx
esophagus
CROP
GIZZARD
esophagus
crop
proventriculus
liver
gizzard
duodenum
small intestine
pancreas
cecum
Pettingill Fig 34
large intestine
cloaca
vent
esophagus
crop
small crop
pylorus
proventriculus
gizzard
Small
Gizzard
Large
and
muscular
Fig. 17-22 p460, PJH
Hoatzin
• Opisthocomus comes from the Greek meaning "wearing
•
•
long hair behind"
Nicknames include:
reptile-bird (because of their crocodilian odor
& harsh monotonous call)
flying cow (because of it's clumsiness in the
air and unusual diet)
Has a diet of leaves…which means it has to have a way
to breakdown cellulose  “______________” stomach
Hoatzin
(Opisthocomus hoazin)
Hoatzin…con’t
• Skeleton modified to accommodate large crop –
•
•
•
fermentation vat housing bacteria that help it
breakdown cellulose to obtain “the good stuff”
(proteins/sugars) in the plant material (not unlike what
ungulates do)
______ bird species that has the “foregut fermentation”
approach to handling plant material containing cellulose
Rests on a sternal callous while lengthy digestion takes
place. The callosity is an elliptical, horny patch of skin
lying over the rear tip of the sternum
Feeds chicks ________________ mush of leaves
Digestive System –con’t
• Length of bird’s intestinal tract averages 8.3 times its
body length. In the common swift, it is only 3x. For the
common ostrich it is 20x.
A) diet—fruit, meat, and insects: __________
B) diet—seeds, plants, & fish: _________
• Near end of digestive tract:
small side sacs called _____
(________ is singular). Attach to large intestine.
A) aid digestion—especially fibrous plant foods
B) produces antibodies
C) aid absorption of H2O
D) aid in metabolism of uric acid into amino acids
Digestive System –con’t
• Overall, digestive system extracts nutrients and energy
•
•
with high efficiency
a) fruits and berries “pass through” in ______
b) other foods (non-fibrous) < _______
Like mammals, some nutrients absorbed by active
transport. Most birds absorb glucose (i.e., simple sugars)
and amino acids by active transport. Other nutrients
passively with other fluids. “______________” requires
little energy…and concentration dependent.
Toxins in fruits and seeds also may be absorbed
indiscriminately
Digestive System –con’t
• Parrots eat seeds and bitter green fruits—many full of
•
•
toxins that are distasteful and lethal to other animals
Some parrots eat dirt…long thought to simply provide
grit for the gizzard. ____________ in ‘dirt’ has minerals
that are _______ to toxins. Kaopectate, which consists
partly of clay, soothes human upset stomachs in this
way. - charged sites of clay minerals “bonds” to +
charged toxin molecules
Some variable stomach designs among seed-eaters.
Notably the phainopela—in the gizzard, the
exocarps from mistletoe berries “off” to the side,
then pass in “packet” until excreted (see next slide)
phainopelpa
Gill Fig 6-21
Digestive System –assimilation efficiencies
• Raptors: 66-88% energy of ingested meat and fish
• Herbivores: 60-70% energy in young plants
• Herbivores: 30-40% energy in mature foliage
• Spruce grouse: 30% in spruce leaves…a very hard-todigest foliage
• Fruits provide “predigested” nutrients in the form of free
amino acids (vs. proteins) and in the form of simple
sugars (vs. complex carbs). Such easily digest and
absorption allow the 20 minutes or less pass through
time
Digestive System –Fruits & Fruit-eating birds
• ______________________________ favored by cedar
•
waxwings. Because of “abundant” glucose and fast
passage through the GI tract, lots of glucose is in the
semi-digested fruit pulp just before evacuation. Cedar
waxwings may be unique in that they absorb this “extra”
glucose via active transport in its rectum.
--also, this “junkfood” diet preference
requires protein-rich cottonwood catkins
to supplement their diet
_______________________________ favored by North
American thrushes
Digestive System –Sucrose…no Sucrose
• Many passerines ______________________—a complex
•
sugar because they lack sucrose, the enzyme facilitating
breakdown of sucrose to glucose and fructose. Ingestion
of high concentrations by such species can cause
sickness and diarrhea—resulting in ____________…thus
they avoid it. Ex. Common starling
In contrast, hummingbirds feed on sucrose-rich nectar.
They assimilate ________ of the energy in nectar. Do
this rapidly by means of unusually high densities of sites
that actively bind sugar and transport it across cell
membranes.
Changes in Starling GI tract
• Response to ___________ availability of certain
food types
• Higher plant content in diet (need more time to
digest to extract nutrients) results in longer
intestinal tract (~ _____ increase in length)
• Besides anatomical changes, digestive enzyme
composition changes, too, to different food types
they consume:
a) simple sugars in fruit
vs.
b) fat and protein in animal-based food
Starling (Sternus vulgaris)
Plant material in diet
length of intestine
Fig. 17-23 p461, PJH
Feeding & Digestion
• Many specializations—especially with respect to
beak & tongue designs
• Beak designs include:
insect catchers
insect net
fruit plucker
generalized bill
flesh tearer
dip net
fish grasper
fish spear
mud sifter
water strainer
seed cracker
pine seed extractor
• For _______ species,
ability to raise the tip
of the bill without
opening the mouth
provides opportunity
to exploit food
sources in the sand
(some shorebirds)
and/or soil
(woodcock)
• Woodcock shown
here has beak that is
3+ inches long—
probes for
earthworms
Fig. 17-19 p457, PJH
American woodcock
Woodpecker—probing tongue
Mammal-version
Anteater---probing
tongue with different
origin for tongue
attachment (on sternum)
but same result
Fig. 17-20 p458, PJH
food-straining (NORTHERN SHOVELER DUCK)
fish-eater (sooty shearwater)
Fringed, tubular nectar feeder
(bananaquit)
general feeder (robin)
fruit-eater (Diard’s trogon)
probing-spearing (woodpecker)
NECTAR FEEDERS
magnificent hummingbird
green violet-ear hummingbird
fiery-throated hummingbird
volcano hummingbird
• Note the _____
of the bill
• Note the
__________ of
the bill
Circulatory System
NOTABLE CHARACTERISTICS
• Proportionately large
• 4-chambered—left and right separation
• Overall design: similar to mammals (i.e.,
humans)
Circulatory System
• Most efficient
design of all
among
vertebrates
(along with
mammals)
Pulmonary
circulation
Systemic
circulation
Circulatory System…output
• Heart, liver, kidneys and intestines: 8-10%
• Brain and eyes: 3-4%
• During flight or swimming, cardiac output
allocations to flight and leg muscles, respectively,
_________ dramatically
• Also: _________ empty more completely than do
those of mammals on each contraction. More
___________ in ventricles than comparable size
mammals
Pettingill Fig 35
Urogential System
NOTABLE CHARACTERISTICS
• Because of “exit” anatomy, the urinary system and
the reproductive system considered together—hence
the “urogenital” designation
• “Exit” point is the _______
a) meeting point for urinary system,
digestive system, and reproductive
system
b) Latin for “sewer”
c) same in reptiles, amphibians
• _______ functional ovary
MALE
FEMALE
adrenal gland
ovary
testis
kidney
vas defrens
ureter
large intestine
cloaca
Pettingill Fig 36
vent
oviduct
Excretory System
• Excretion of water and _______________ takes place
in the kidneys and the intestines—and in some
species by the action of salt-secreting glands.
• Relative to most mammal kidneys, bird kidneys are
relatively flat
• Different from both mammals and reptiles:
A) Urine produced by kidneys mixes with fecal
components in the _____________
B) Also, at this point in lower intestine H20 can
be resorbed…as needed
Excretory System…con’t
• Key physiological adaptation: promotion of water
economy is the excretion of nitrogenous wastes in
the form of __________
• Uric acid are the white crystals that give bird
droppings their unusual color.
• Nitrogenous waste a result of body structures that
produces nitrogenous products that become toxic if
allowed to accumulate. For mammals, they handle
this by producing urea in aqueous solution that
requires large quantities of water. Uric acid can be
excreted as a __________________ in which each
molecule of uric acid can contain _______ as much
nitrogen as a molecule of urea
Excretory System… Uric Acid…con’t
• This process of excretion results in huge efficiencies
with respect to ____________:
A) 0.5 to 1.0 ml of water to excrete 370 ml
of nitrogen as uric acid
vs.
B) 20 ml of water to excrete same amount of
nitrogen as urea
• Concentrations of uric acid in the ______—just before
defecation—can be as much as _______ the acid level
in the blood stream! In the mammal world, even the
best at this—kangaroo rats—have concentrated urea
in urine to “only” 20-30 times.
Excretory System… Hummingbirds
• Too much ______ “problem”
• Result of ______ composition—lots of water
• Anna’s hummingbird documented to, on a daily
basis, consume up to _____ its body mass in nectar
• The rate of water moving through and excreted is
among highest known to freshwater amphibians
• Kidneys are not different from other birds, just these
species have highest rates of evaporative water
among birds AND some of the water is keep in the
digestive tract and therefore does not pass through
the kidneys
Excretory System… Salt and Oceanic Birds
• Loops of Henle in avian kidney (i.e., nephrons) are
short compared to mammals. This poses challenge
to birds that drink saltwater.
• Saltwater is about 3% salt. Body fluids are about 1%
• This high concentration increases need to excrete
electrolytes. This salt excretion is aided by presence
of ______________ (Gill Fig. 6-27, pg 178).
A) just above eyes
B) rapid unloading bloodsystem system
C) special “infoldings” of cellular lining of the
nares. Linings contain secretory tubules…
that get salt from ________________ of
the _________________
D) tubules connect to central canal and drip out
Genitals – Male: Testes
•
•
•
•
•
paired
ellipsoid
asymmetry typical—left usually larger
during breeding season, up to ____ increase in size
vas deferens contain the sex cells/spermatozoa from
the testes
• seminal vesicle stores sperm until copulation
• no penis or “external” genintalia. But there are
exceptions. For the most part copulation takes place
via brief cloacal contact: known as a ___________.
More on mating…later in the course
Genitals – Female
• single ovary
• cloaca in female generally smaller but lips of the vent
tend to protrude more conspicuously
• Also, both for males and females—during dissection
of fresh specimens, gonad tissue will be _______ vs.
adrenals which will be highly colored (orange-yellow
usually) and larger.
Summary
• High ___________
• Flight and maintenance of high body temperature
requires large amounts of _________
• Both circulatory and respiratory systems ___________ to
meet these demands by delivering fuel removal of
metabolic wastes
• Adjustments to ____________________ by
a) adjusting plumage insulation
b) shivering
c) evaporative water loss
• Mostly _______ of passage of foods through digestive
system
• Excretion via uric acid minimizes water need…________.