Lecture 2 And 3 Flashcards
What is topography
The look of the animal -external structures
How many species of birds in the world
About 8500
Taxonomically, birds are placed in the Class ___
Aves
What is the primary distinguishing feature of birds
Feathers
How do birds birth their young
Laying eggs
Called Oviparous
What are the only other species that flies besides birds
Bats
The epidermis of birds is made of thin, flat epithelial cells that produce keratin, what structures is this necessary for?
Outer sheath of beak and claws
Feathers
The dermis is a thicker, fibrous connective tissue layer, what are the two main things the dermis is responsible for
Storage for fat
Movement of muscles via smooth muscles (heat regulation)
True or false
Birds have sweat glands
FALSE
What is the uropygial gland, what does it do?
The preen gland
Found on the dorsal surface at the base of the tail feathers
Secretes an oily fatty substance that waterproofs feathers
Varies in size with species
Lacking in some species (parrots or flightless birds)
Birds put the oil on their beak and rub it all Over their feathers
What do birds that do not have a preen gland often prefer rather than water baths
Dust baths
Describe the beak of birds, what determines their shape?
Derivative of a birds skin (keratin formation) it is covered in a horny keratin layer
Varies in hardness, flexibility and shape based on the function and what the bird eats
True or false
Bird beaks grow continuously
True
If a bird’s beak grows continuously, what does this mean?
Must be provided surfaces and foods that will maintain a normal length of the beak
Maybe need to clip or file the beak in some cases of overgrowth
What can overgrowth of the beak indicate
Internal problems
Nutrient problems
Describe the claws of birds, how do they differ between species?
Ends of each toe, possess horny sheath derived from specialized scales
Grow continuously
Differ based on perching habits and how the procure food (hunting or not)
What does it mean when you “quick” a birds nail
When you cut too deep and hit the blood vessel within the nail
True or false
Feathers are living structures on the bird
FALSE
they are non living structures
Describe feathers, what are their 5 main functions
Outgrowths of skin made of protein
Functions
1) flight
2) protection
3) thermoregulation
4) camouflage
5) communication behaviours
Where do feathers have sensation
At the base of the feather, in the area of attachment, not the actual feather
Describe the anatomy of feathers
Quill/calamus: hollow tube below the fluffy part of the feather (no barbs on this part)
Rachis: continuation of the quill with barbs attached
Bards: individual hair strands
Vane: a group of barbs held together by hooklets and barbule
Distal and proximal umbilicus: distal is a hole at the start of the barbs, proximal is the hole at the end of the quill
What are contour feathers
Most visible feathers
Give shape to the bird
Most compact microstructure: quill, rachis, vane (barbs, barbules, hooklets)
Have a tight structure on the fluffy part of the feather -held together. Often contain the color of the bird
What are semiplume feathers
Commonly found under contour feathers (mainly on sides, necks and back)
Provide insulation, flexibility and buoyancy in water birds
Central rachis with free barbs (no barbules or hooklets) (barbs not held together)
What are down feathers
Soft, fluffy, located next to the skin
Function in insulation
No rachis, simply a calamus with free barbs
What is a powder down feather
A specialized type of down feather
never stop growing (most other feathers stop at a certain point and fall out to get replaced)
Disintegrate at the tip, creating a waxy powder -this spreads on the plumage through preening, it helps clean and waterproof the bird
Highly developed in birds with out a uropygial gland (some parrots)
What is a filoplume feather
Sensory or decorative in function
Elongated rachis with barbs only at the distal portion
What are bristle feathers
Modified contour feathers
Thought to serve as a sense of touch
Location depends on species
Long, tapered rachis, few or no barbs at the base of the rachis (may or may not have barbules)
True or false
Feathers originate all over the body
FALSE
feathers overlap and are laid down in tracts with areas of bare skin in between
What is apteria
Where feathers do not grow on birds (bare areas)
What is molting
The process of replacing feathers
Occurs in species specific patterns (allows birds to continue on with life)
Generally a gradual process
Usually occurs symmetrically on the body
Only one or two major flight feathers at a time
When is the major molting time
Fall
What is different about water fowl molting
They lose all their feathers at once following the breeding season
Where do feathers grow from
From papillae in feather tracts of the dermis
What pushes out an old feather
A newly developing feather
Describe what feathers first grow covered in
Emerges covered in periderm
This is removed by preening
The blood vessels of a feather from the dermis reach into new feathers, what happens when the feather is mature?
The blood dries up and the rachis is pinched closed
Should appear white in adult feathers, may be blue in young feathers (important for wing clipping)
What is the objective of wing clipping
Clipping the feathers so the bird cannot fly (get lift) but can still glide down if they fell from a perch
Describe how to clip a birds wings
Trim 5-7 flight feathers under the coverts , this leaves a smooth appearance
Trim the outermost feathers OR leave two or more outermost primary feathers intact
Why should you not trim blood feathers (immature feathers) or the feathers on either side of it
These will cause major bleeding when cut
Don’t trim the ones on either side of it as protection from breaking
Where do the primary flight feathers originate from
The “hand” (metacarpus and digits)
Where do the secondary flight feathers originate from
Radius and ulna
What are the major and minor coverts
The feathers that cover the starts of the flight feathers
What do external parasites do to feathers
Chew and consume parts of the feather vanes, creating weak points
Damage to feathers can also be due to daily
Wear and tear
What is a fault bar
A stress bar
Weakened area in the feather vane where barbs lack barbules
Feather is stressed during its growth when blood flow is disrupted
What is the most common stressor for birds
Poor diet
What is feather picking
Common in captive psittacines and imprinted raptors
Can be caused by boredom or disease (parasites, infection, toxins)
Over picking of the feathers
If feather picking is seen in small birds it is almost always due to a
Medical cause
If feather picking is seen in large birds it is almost always due to a
Behavioural issue
Which cause of feather picking is harder to treat
Behavioural
What are the modifications of the musculoskeletal system of birds that allow for flight and walking
Reduction in number of bones
Fusion of some bones to form plates (keel)
Reduction in bone density
Loss of internal bone matrix (hollow, air filled spaces)
What is the axial vs appendicular skeleton
Axial: skull, vertebrae, sternum (framework)
Appendicular: wings, shoulders, legs, pelvis (locomotion)
Describe the skull of a bird
The jaw bone extends into the keratinized bill
Have large eye sockets bordered by sclerotic ring
Very Small portion of skull devoted to the olfactory system
True or false
Birds have a greater number of cervical vertebrae to allow for further flexibility
True
Describe the thoracic vertebrae of birds
Rigid to provide strong support for ribcage
Have the uncinate process that overlap adjoining ribs
Describe the lumbar and sacral vertebrae of birds
Fused vertebrae form bony plate to support legs (synsacrum)
Describe the coccygeal vertebrae of birds
First few mobile to allow movement of tail feathers
Pygostyle: fused bony structure that supports tail feathers
True or false
Lumbar and thoracic vertebrae do not move
True
Describe the sternum of birds
Large and concave
Protects the chest
Acts as a place of origin for flight muscles (keel) (pectoral muscles are the flight muscles)
The shoulder bone is a complex of 3 bones, describe these
Coracoid: prevents the collapse of the whole structure from the force needed to push wings together
Scapula
Clavicle (wishbone): fused clavicles are called a furcula
True or false
Muscles to open and close wing span are both on the back of the bird
FALSE
there are both located on the CHEST, very little muscles on the back
True or false
There is more force needed for the down stroke during flight
True
Describe the movement of the shoulder
Allows several planes of rotation
Wing muscles attach at the
Pectoral crest of the humerus
The humerus of birds is longer in birds that
Glide and soar
Describe the movement of the elbow
Only allows movement parallel to the wing
What is the patagium (propatagium)
The web of skin that extends from shoulder to wrist
Assists in aerodynamics
What is the alula bones
First digit that originates from the wrist
Carries the alula feathers (steering) for fine control
Describe the metacarpal bones
Metacarpal bones (Fused to form major and minor metacarpals) (2 in total) join with digits 2, 3 and 4
These help support primary flight feathers
Describe the pelvis of birds
3 paired bones join where leg attaches to body (ileum, ischium, pubis)
Distal ends of pubis not fused: Provide room to facilitate egg laying
Describe the legs of birds
Femur is directed forward to the knee
Some tarsal bones are fused with the tibia forming the tibiotarsus
Some tarsal bones are fused with the metatarsals to form the tarsometatarsus
Single bone of the “hock” spans from the ankle to the digits
Describe the feet of birds
A metatarsal pad on the bottom of the foot surrounded by 2, 3 or 4 digits
3rd toes is usually the longest
What are anisodactyl, give some examples of these
One toes faces to rear, other 3 face forward
Galliforms, raptors, song birds
What are zygodactyl
2nd and 3rd toes face forward
1st and 4th toes face backwards
Parrots
describe “bumble foot”
Infection of the feet, usually from a staph infection
Causes severe swelling, ulceration and discomfort
Linked to perches that are all the same size, too rough or not rough enough, or long claws
Change the perches and treat with antibiotics and preparation H (topical)
Why is it difficult to treat feet problems in birds
Birds are always on their feet, walking in feces especially
Infections spread fast since there is little tissue surrounding and very close to bone
Many muscles of birds are placed
Ventrally, near the center of gravity
What are white fibers in muscle
Thick
Low blood supply
Little myoglobin
Use stores of glycogen
Found in flight Muscles of short distance fliers
Exhausts quickly
“White meat” in breasts of birds
Sprinting, short bursts of flight
What are red fibers in muscle
Thin Large blood supply Fat Lots of myoglobin Mitochondria
Found in flight muscles of long distance fliers
Dark meat (legs)
Marathon runners, flying for long distances
Describe what muscle fibers birds have depends on
Depends on lifestyle of birds (fliers vs walkers)
Some muscles have one or the other or a combination of both
Describe the movement of wings in flight and the muscles involved
Both muscles found on the chest, responsible for raising and depressing the wing
The pectoralis muscle is larger and more superficial, flexion causes the wing span to close (down stroke)
The supracoracoideus is smaller and deeper, flexion causes the humerus to move and the wing span opens (up stroke)
What is the muscle of choice for IM injections in birds
The pectoralis muscle
Describe the muscles of the legs in birds, how are the toes controlled?
Primarily located over the femur
Control movement of the toes through long tendons
What is the perching reflex
Claws close as the leg flexes
Allows bird to remain perched while sleeping (won’t let go or fall off)
How can the perching reflex be used when clipping nails
Extend the leg to open the claws
Describe the muscles of the head and neck
Extent of the jaw muscles vary depending on diet (strength needed to eat specific foods -hard nuts vs seeds)
Neck muscles allow movement in different directions
What is the hatching muscle and the “egg tooth”
These structures aid in the new born chicks to break through their shell
The hatching muscle is on the back of the neck to give power when breaking shell (atrophy after birth)
The egg tooth is a small cornified structure on the beak to aid in breaking
Describe the brain of birds, what differs compared to mammals
Large in proportion to its body
Location of different centres are similar to mammals but they have a large center for vision and hearing, and a small center for taste, touch and smell
Describe the vision of birds
Highly developed
Large portion of the skull is made for housing and protecting the eyes (shape of the eye depends on the orbits)
Has limited movements in some species (most have to move their entire head rather than their eyeballs -owls)
What is the shape of diurnal birds’ eyes
Round or relatively flat eyes
What is the shape of nocturnal birds’ eyes
Tubular (elongated)
What are the 3 main devisions of the anatomy of the eye
Fibrous tunic
Uveal tunic
Neural tunic
What does the fibrous tunic contain, what are some specialized structures in this area in birds
Sclera and cornea
Birds have a sclerotic ring that reinforces the sclera
Nictitating membrane (third eyelid)
Describe what would be different about a diving bird’s nictitating membrane
May have a clear center so they can see under water -protects the globe
What does the uveal tunic contain, what is the main difference here in birds compared to mammals
Choroid, iris, ciliary muscles
Muscles in the iris are under VOLUNTARY control
If the muscles in the iris are under voluntary control, what does this mean for the pupillary light reflex test
In birds, this is NOT considered a reflex, when a light is put into the eyes, the bird is literally choosing to constrict their iris
What does the neural tunic contain
Retina
describe the vascular pecten in the eye
This is a highly vascular comb like structure that projects into the vitreous humour from the point of the optic disc.
This provides oxygen and nutrients to the eye and removes waste
Can easily hemorrhage with head trauma and will see bleeding from the eyes
This structure is present because they have a reduced number of blood vessels in the retina to allow more photoreceptors (rods/cones)
true or false
Nocturnal species have more cones than rods
FALSE
they have more rods than cones
Rods: low light vision
Cones: color vision
Describe how birds have a higher level of visual acuity
Reduced number of blood vessels in the retina to allow more photoreceptors
Each cone has a single connection to a nerve fiber
Oil droplet in each cone increases color reception
Wide spectrum of light wavelengths are able to be perceived
Some species have a temporal fovea in the eye, what does this do
Increases binocular vision
Describe the ears of birds, what are some main differences
Located on the sides of the head, behind and slightly below the eyes
Do not have much of an external structure like a pinna
The middle ear only contains ONE bone (mammals have 3) called the Columella
What makes the nocturnal owls hearing so highly developed
Contain a operculum: a muscularly controlled flap of skin in the ear that opens and closes to allow focusing of the ear
Also have asymmetrical ear openings to allow them to pin point where sounds are coming from
Large eardrums, columellae and cochlea
Well developed acoustic center in the hindbrain
Large number of auditory nerves
Describe the tasting ability of birds
Poor sense of taste
Very few taste buds scattered on the sides of the tongue and soft palate
Levels of sensitivity and thresholds to taste vary in species (most can only differentiate types of taste -bitter, sweet, salty)
Describe the sense of smell in birds
Highly variable in species depending on diet (hunting birds have a better sense of smell)
True or false
If you pick up a baby bird from its nest, the mother will abandon it because it smells like humans
FALSE
this is a myth
Describe the two main nerve endings for sense of touch in birds
Grandry’s Corpuscle: nerve endings prevalent on tongue, palates and bills of birds
Herbst Corpuscle: nerve endings present on cloaca, legs, wings, uropygial gland and feather bases
What is the main difference of the endocrine system of birds
7 major glands plus the pancreas all function similar to mammals
The Bursa of Fabricus is the initial site of B lymphocyte production (rather than in the bone marrow in mammals)
Because birds have such a fast metabolism, what does this mean for their diet?
They require large amount of food for the high energy demand
Beaks of birds vary with
Diet
The mouth of birds is similar to mammals, containing hard and soft palates, tongue, salivary glands and taste buds, what is the main difference in some birds?
Some species have a soft palate that enlarges into a pouch for temporary food storage (pelicans)
What is the main difference of the hard palate in birds, what is it used to evaluate
Hard palate has an opening that communicates with the nasal cavity (choanal slit)
Used to evaluate papillae for nutritional deficiencies
Describe how the tongue varies With Species
May be highly muscular in some species
May have very few muscles and is moved by muscles of the jaw apparatus in other species
Describe the main difference in the esophagus of some species of birds
Contains a Crop
And expansion of the esophagus over the interclavicular space
This is a place for storage, lubrication, passage and potential mechanical break down of food
Very little digestion occurs here
Describe the crop in pigeons and doves at breeding time
Mucosal lining can break down and slough off to form “pigeon milk”
Describe the crop in Insect eating birds
Heavy epithelium protects the crops when insects are swallowed alive
Describe the stomach of birds
Two separated compartments
Proventriculus: glandular compartment -chemical digestion begins here with pepsin and HCL
Ventriculus or Gizzard: muscular stomach: striated muscles grind food (mechanical) ingested grit aids in grinding food here (rocks)
What is the pellet
Indigested food ground into a pellet in the ventriculus gets regurgitated
In birds of prey the pellet is mainly formed of bone, fur, etc -parts that couldn’t be digested fully
Describe the liver of birds
Bilobed - right lobe is larger than the left
Describe the pancreas in birds
Relatively large especially in fish and grain eaters
Rests in loop of the duodenum
Endocrine portion occupies more tissue mass than in mammals
Describe the duodenum in birds
Main organ for digestion and absorption of nutrients
Varies in length and thickness depending on diet
Describe the ceca in birds
Paired sacs at the junction of the small and large intestines in some species
Role in water reabsorption and in bacterial fermentation of cellulose
Contents excreted independent of fecal material
Describe the large intestine in birds
Major role in reabsorption of water and minerals
what is the cloaca
The end of the digestive tract
Common exit for the digestive, urinary and reproductive systems
Describe the 3 sections of the cloaca
Coprodeum: receives excrement from the intestines
Urodeum: receives discharge from the kidneys and genital ducts
Proctodeum: stores excrement and eliminates it
All 3 things get combined/stored before excretion
What is the vent
Muscular anus that expels waste products (mute)
Waste excreted by birds is called
Mute
Describe mute
Combination of feces (dark) and urine (liquid) with white powdery urate around it
Varies with diet
How can mute be used to assess health
Can be an indication of disease based on color
Green mute can indicate chlamydial infection (zoonotic), internal parasites or liver disease
Why should owners be familiar with the appearance of mute in their birds when they come to clinic?
Because stress can change how the mute looks while in clinic
Encourage to take a photo
Why can birds technically not vomit
They have no diaphragm
Describe tube feeding birds
Trachea is a small hole found more rostral in the throat, the esophagus is more caudal
Watch the back of the throat for regurgitation/over flow -indicates you put too much food in (risk of aspiration since trachea is so close and there is no real epiglottis present)
Describe the heart and where it lies in birds
4 chambered, right side is smaller and less muscular
Lies in the cranial portion of the thoracoabdomnial space (called this since there is no diaphragm that separates the cavities)
Why do birds have large pectoral and brachial arteries
To meet the specific demands of these highly muscular portions of the body (need a lot for flight)
Describe the renal portal system of birds
Blood vessels from the legs/lower body, returning to the heart is shunted to the kidneys to get filtered before returning to the heart
Why should the renal portal system in birds be taken into consideration before injecting medications
Would want to do it in the upper body so the medication can spread systemically before it gets filtered out by the kidneys
Describe the countercurrent heat exchange system in the legs of birds
A system of heat exchange in lower extremities through a network of arteries and veins placed closely together
Heats up blood from the extremities before reaching the core to prevent hypothermia, and colder temperatures are sent with arteries back to the extremities
Does not constantly occur (like in summer) -has a sphincter that opens/closes depending on temperature
Especially useful in swimming birds
Since birds have a fast metabolism, what does this mean for heart rate and blood flow
Fast heart rate
More rapid blood flow
Electrodes used in electrocardiography are placed on
Wings and legs
Functions of blood
Carry nutrients, oxygen and hormones
Carry metabolic wastes to lungs/kidneys
Control/prevent disease
Regulate body temperature
What is the main difference of erythrocytes and thrombocytes in birds compared to mammals
They are nucleated
What are neutrophils called in birds
Heterophils
Describe erythrocytes in birds
Oval, nucleated and larger than mammals
Formed in bone marrow in adults or in spleen/liver in some species
Posses hemoglobin
Total number dependent on age, sex, diet and time of year
Describe heterophils in birds
(Neutrophils)
Phagocytes
Round with rod shaped red/orange granules
Bilobed nucleus with clumped chromatin
Describe thrombocytes in birds
Birds do not have platelets, they have THROMBOCYTES
nucleated cells that act as platelets do
Smaller than RBCs with large, round/oval nucleus
Produced by bone marrow in adult birds
why do birds have such an extensive respiratory system
High demand due to fast metabolism and high energy levels (fliers)
Also aid in buoyancy during flight
Describe the trachea of birds
Longer in comparison to body than mammals
Provide moisture and heating of inhaled air and aids in sound production
Have cartilaginous rings that surround the entire structure (not just c shaped)
May be coiled in some species
What is the syrinx
The voice box
Enlargement of the trachea above the sternum
Contains muscles, air sacs and vibrating membranes
Vocalization complexity depends on
the number of muscles present in the syrinx
Describe the bronchi of birds
Trachea bifurcates into 2 bronchi
These further divide: Mesobronchi: in the lung Secondary bronchi: ventrobronchi Parabronchi Air capillaries (site of gas exchange)
Describe the lungs in birds
Small and inelastic (do not expand/contract) High vascular (bright red)
Attached to the thoracic vertebrae and ribs
Connect via projections into the bone that put air into the hollow spaces for buoyancy
Describe the air sacs of birds
9 think walled high vascular membranes
Connect to the bronchi -some extend into bone cavities
Functions: Air reservoirs Provide warmth and moisture to air Thermoregulation Buoyancy
Respiratory rate increases with
Activity, heat, flying high
Describe the airflow in birds lung
2 inspirations and 2 expiration are required to transport one breath of air through the entire system
Path of one breath/air pocket:
1st breath in: goes into posterior air sacs
1st breath out: goes into lungs
2nd breath in: goes into anterior air sacs
2nd breath out: air leaves
If birds have no diaphragm, how do they breath
It is a whole body process driven by the expansion of the chest cavity/ribs
What is different about a birds trachea? What does this mean for restraint
Birds tracheas have cartilaginous rings that surround the entire structure (not a c shape)
Restrain mainly from around the neck since breath occurs with the chest cavity movement
True or false
There is no mixing of inspired and expired air with birds
True
Due to their very efficient respiratory system, what does this mean for inhaled chemicals
Very rapid response and increased sensitivity to inhaled anesthetics
Very sensitive to poisonous gases or inhaled irritants
Ex: Teflon pans can cause respiratory distress and death in birds
Ex. canaries used in coal mines (these would die due to poisonous gases before humans did, used as an alert system)
Describe the respiratory rate in birds
Varies with species, activity level, age, sex, time of day, outdoor temperature
Smaller birds breathe faster than larger birds
Birds in flight have higher rate than non flying birds
Respiratory rate is usually very fast and very high so it is not often used as a diagnostic tool
True or false
Intubation of birds is extremely easy
True
trachea is very easily visible
Describe how birds thermoregulate
Birds have no sweat glands
Most heat is eliminated through respiration (water evaporated through respiratory system helps cool)
Can increase this rate by panting or fluttering the upper throat patch with an open beak
Why is panting dangerous in birds
Often indicates stress or over heating
Birds exist at a higher temperature compared to mammals, this leaves very little room for temperature changes before proteins begin to denature etc
What are some other methods of decreasing temperature in birds
Bathing
Decreases activity
Some species defecate on their legs to increase evaporative cooling
Adjusting feather position (poofing to warm) (open up bare patches to cool)
Other methods of raising body temperature in birds
Perching on one leg to minimize skin exposure
Tucking head and beak under feather on back
Shivering
Seeking shelter
Some species (humming birds) can enter a temporary night time torpor (state of inactivity) to conserve heat
Countercurrent heat exchange in limbs
What is the urogenital system
The urinary and reproductive system in birds
True or false
Female birds only have one ovary on the left side
True
What is the salt gland
Many marine birds have a “salt gland”
Located above each eye and they drain into the nostrils
Secrete large amounts of sodium chloride (salt)
Helps maintain ideal osmotic conditions in the body while living and feeding in a high salt environment
Describe the kidneys in birds, what are the differences compared to mammals
Large paired organ, 3 lobed, Lie flush with the back bone
Renal portal system filters blood from lower body (controlled by a valve)
Similar in function to mammals but
1) there is no renal pelvis
2) 2 types of nephrons: looped (similar to mammalian nephrons) and unlooped (similar to reptilian nephrons)
True or false
Birds do not have a urinary bladder
True
Excrement from kidneys get collected in the urodeum of the cloaca
Describe the urine composition of birds
Different from mammals:
Higher concentration of uric acid (urea is predominant in mammals)
Uric acid is Eliminated as a white powder in combination with fecal material (usually green or brown with a ring of white around it (urate))
Why is the different urine composition of birds more advantageous
More efficient way to get rid of nitrogenous waste:
1) Less water loss
2) Allows embryo to store large amounts of nitrogenous waste with the confines of the shell without dying (wouldn’t be possible with urea since urea is toxic and uric acid is not)
Breeding season in birds is often stimulated by____. What does this affect in the bird
Increasing day length in parts of the world where seasons are more pronounced
This affects the hypothalamus and causes an increased secretion of gonadotrophic hormones
Non breeding animals have very small gonads, which increase in size when
Breeding season approaches
How are most birds differentiated by sex
Many species have very little sexual dimorphism, so the only way to tell sexes apart is by DNA testing (blood test)
Describe the testes and where sperm is stored in birds
Testes are bean shaped and located internally
Sperm are stored in a pouch called the seminal vesicle (temp here is 4 degrees cooler than body temp) located at the terminal end of the vas deferens
The vas deferens carries sperm to the
Seminal vesicle and cloaca
Describe copulation for males
Behaviour stimulated by androgens (from leydig/interstitial cells in the testes)
Some species (galliforms, ratites, and ducks) have a grooved penis that assist in sperm transfer
Other species simply bring cloaca together for copulation
True or false
Basic ovarian follicles development and ovulation in birds is similar to mammals
True
Transfer of the ova into the oviduct is similar in birds to mammals, what differs as the egg passes through the oviduct and uterus
The eggs get surrounded by layers of albumin (egg white) the shell membrane, shell and pigments
This means the ova is the egg yolk in an egg
Birth of the eggs is through the
Cloaca
What are the 5 sections of the genital tract in females, how do these 5 sections contribute to the development of the egg
1) infundibulum: catches the ovum when released from ovary, fertilization occurs here
2) magnum: secrete albumin
3) isthmus: secretes inner and outer shell membranes onto fertilized ova
4) uterus (shell gland): secretes thin watery albumin, the shell and pigmentation, the eggs spends most of the time here to form egg (uses a lot of calcium)
5) vagina: secretes mucus for egg laying and stores sperm for hours to days
What is egg binding/ egg bound birds and why is it considered a medical emergency
When the egg fails to pass from the uterus to the cloaca
Since the bird only has one opening for the reproductive, urinary and digestive systems, when and egg is blocking here it prevent urination and defecation (can die very quickly)
Signs: depression, stop eating, penguin like gait
How do you treat an egg bound bird
Anti-inflammatories
topicals, baths, calcium supplements, manual manipulation or surgically by collapsing the egg with a needle through the cloaca
How do you prevent egg binding
Avoid obesity
Watch for vent picking and separate affected birds
Ensure adequate calcium in diet
Define clutch
The number of eggs laid and incubated
Varies in species (1-20)
What are determinate layers
Total number in clutch Predetermined by number of follicles developing on the ovary
What are indeterminate layers (most birds)
Eggs are continuously produced until a set number is reached in the nest
If eggs are removed the bird will continue to lay indefinitely
The signal to stop includes visual, tactile and hormonal influences indicating a full clutch (birds literally counts)
Why are indeterminate layers beneficial with endangered species
Will remove eggs and incubate artificially so the bird will continue laying
Eggs can be laid every day, every other day, or every 4-5 days
Some species incubate all at once or as eggs are laid
What can this result in
Chicks may all hatch and develop at varying times
Or chicks may all hatch and develop synchronously
How to birds incubate the eggs
Sitting on the eggs/nest to keep eggs at a certain temperature in order to develop (need to be kept warm and humid)
Females have a “brood patch”: featherless patch on the belly where skin folds, thickening and blood circulation create a “heat pad” for eggs
Time for incubation varies with species (longer for larger birds) (budgies: 18 days)
What do the 4 classifications of chick depend on?
Feather coverage
Open or closed eyes
Mobility
What are precocial chicks? Give an example
Ducks and geese
Downey feathers, open eyes, mobile
What are semiprecocial chicks? Give an example
Gulls and terns
Downey feathers, open eyes, may be mobile but remain in nest and dependent on parents
What are semialtricial chicks? Give an example
Hawks and owls
Downey feathers, open (hawks) or closed (owls) eyes, not mobile
Confined to nest for care
What are altricial chicks? Give an example
Song birds
Little to no feathers, closed eyes, not mobile
