Lecture 1 -- Anatomy and Physiology of Birds

What classification kingdom do birds belong to?

Animalia

What is the phylum for birds?

Chordata

To which class do birds belong?

Aves

Which group of birds does the bird shown in the picture belong to? What are they also called? What are its features?

• Passerines 

• = Songbrids/ Perching birds 

• Four toed, one pointing backwards 

What are commonly kept songbirds?

Finches, canaries, and mynah birds.

What is the order for parrots?

Psittaciformes (Psittacines)

List three types of small parrots that are commonly kept

Budgies, lovebirds and cockatiels 

List three types of big parrots that are commonly kept

African grey, Amazon and Cockatoo

Raptors are divided into three orders. What are these orders, and what birds are included in each?

• Accipitriformes - Diurnal birds e.g. Hawks 鷹, Buzzards 

• Falconiformes - Diurnal birds e.g. Flacons 

• Strigiformes - Nocturnal birds e.g. Owls 

What types of birds belong to the order Anseriformes?

• Duck 

• Geese 鵝

• Swans 天鵝

What types of birds belong to the order Galliformes?

• Chicken

• Turkey 

• Peacock 

• Quail 鵪鶉

What types of birds are classified as ratites? Why those birds are classified as ratites?

• Ostrich + Rheas

• They are flightless birds with no keel 

What is the order for chickens and turkeys?

Galliformes.

List the anatomy of the chicken 

Ratites not being strictly a taxonomic term.

Try to list out all the features of bird’s eyes

• Huge eyes (Up to > 50% cranial volume in some birds)

• Have sclerotic rings to support the eye balls

• Have ability recognise UV → Enhance vision for communication, behaviour and hunting

• Rarely blink → Eyelids only closed when sleeping

• Have third eyelid, which functions as blinking

• No meibomian gland → Harderian and lacrimal gland are the main source of tear production

• Thinner cornea + Softer lens → Allow more movement in the lens, which allow for visual activity

• Thick and avascular retina

• Have pecten (Out-folding of retinal surface)

What features of the eyes in birds are similar to those in mammals?

• Have anterior and posterior chamber as in mammals

Which eye feature is absent in birds?

• No meibomian gland (Harderian and Lacrimal gland)

What structures support the eyeball in the eye socket of a bird?

Sclerotic ring 

What is the function of the third eyelid in birds? Why?

Blinking as they rarely blink (They only close their eyelids when sleeping)

What are the major differences in the cornea, lens, and retina between chickens and mammals?

• Retina is thicker and avascular

• Lens is softer (Allow more movement), Cornea is thinner

What are the adaptations found in the eyes of raptors (birds of prey)?

They have the ability to recognise UV/ polarised light → Important in communication, behaviour and hunting

What is the pecten in the eyes of birds? What are its function?

• Pecten is out-folding of the retinal surface

• Rich blood supply

• Function: 1. Retinal nourishment 2. Acts as a sunshade → Reduce light reaching the retina

What features of the ears in birds are similar to those in mammals?

Comprises outer, middle and inner ear

What feature of the ear in birds is absent in their outer ear?

No external pinna

If birds lack an external ear (pinna), what protects their outer ear, and what are the other functions of this protective feature?

• Protected by auricular feathers

• Act to funnel sound towards ear

Compared to mammals, are the glands present in birds increased or reduced?

• Greatly reduced 

• No sweat glands, no sebaceous gland 

What glands are present in birds but not in mammals? Where is it located? What is its function?

• Uropygial gland (Preen gland) 

• Located at the dorsal surface of tail 

• Produces lipid rich secretion for feather waterproof and maintenance

What types of birds have a uropygial gland, and which species do not?

• Largest in aquatic birds

• Not present in ostrich, emu, some pigeons and some parrots

Compared to mammals, what are the special features of the integumentary system in birds?

• Skin of most birds is thin and inelastic, especially in the strigiformes (owls)

• Modified on limbs → Scales can be observed in their limbs 

For bird species that do not have a uropygial gland, what adaptations do they have instead?

The birds who don’t have the uropygial gland have a slightly different type of feather (power down feather) → They produce a lot more dust on their feathers and that helps with the waterproofing and feather maintenance  

Name all the features of a feather.

What are the features of rachis?

• Contains capillaries during growth phase → Loses them and becomes hollow as feather matures

What are the features of calamus?

• Hollow → Anchors feather into follicle

What are the features of vane?

Vane = Either side of central rachis

• Consist of series of barbs with interlocking barbules

List the different types of feathers in birds, along with their location and features.

• Contour feather (Outermost feathers) → Give colour and “contour” and protect from the elements

• Semiplumes (Under contour feathers) → Loose structure that provide insulation

• Down feathers → Very loose structure with no barbs that provide insulation

• Power down feather → Specialised down feather where tips of barbules disintegrate during preening → Provide a waterproofing effect

What are the three types of contour feathers, and what are their functions?

Coverts - Small contour feathers of the wing

Remiges - Large contour “flight feather” of the wing

Retrices - Tail feathers

What types of birds tend to have powder down feathers?

Can mostly seen in birds with reduced or absent preen gland

Name different regions of a wing feather

Name the areas in the below pictures

What are pterylae? 

Feather follicles confined to well defined areas

What are apteriae?

Area that has no feather follicles

What are the characteristics of blood feathers?

Growing feathers with a huge blood supply and nerve supply 

What happens if a blood feather is broken?

It bleeds and does not grow back until the next moult.

How frequent does birds moult?

Generally once a year (some species might be slightly different)

What factors affect moulting?

Season, temperature and nutrition factors

What is required for moulting in birds?

Increased energy intake

If feathers are damaged during handling, when will they grow back ?

Next moult because the shaft is still left in

If feathers are plucked when will they grow back?

Immediately

Why wing clipping is controversial? 

Wing clipping affect bird’s behaviour, ability to fly and well-bing 

What is the aim of wing clipping? 

To reduce ability for vertical lift , not stop them flying completely 

What are the different techniques of wing clipping?

• Bilateral vs Unilateral

• Primary vs Secondary feathers

• All (Complete primary feathers) vs some (Part of the primary feathers)

What is the effect of unilateral wing clipping?

Imbalance → Crashes landing 

What are the main functions of skeletal system provided in birds

1. Flight

2. Egg production

3. Respiration

How does the skeletal system support flight in birds?

1. By reducing weight 

   • Fused bone e.g. Fused area of spine, fused pelvis, fused lumbar vertebrae and fused leg bones  

   • Lightweight structure 

   • Small skull relative to body size 

   • No teeth (They’ve modified teeth into beak)

2. By providing attachment points for flight muscle 

   • Keel 

   • Coracoid → Stick up with the scapula → Stop the thorax being compressed by those strong wing muscle when they are flying = Prevent chest compression 

How does the skeletal system support respiration in birds?

• Some of the bones are hollow and house extensions of the air sacs

How does the skeletal system support egg production in birds?

• Medullary bone provides a source of stored calcium during times of peak egg production

What is unique about the bird skull?

• No teeth

• Sclerotic rings supporting globes

→ Help them to reduce the thickness and the weight of bone in the skull

How many cervical vertebrae do birds have?

11 to 25 cervical vertebrae.

Most vertebrae in birds are fused. Which ones are they?

• Cervical vertebrae - No fused

• Thoracic vertebrae - Fused as notarium

• Lumbar, sacral and some caudal vertebrae - Fused as synsacrum

• Final few caudal vertebrae - Fused as pygostyle

What is the function of the fused thoracic vertebrae (notarium) in birds?

Resist twisting forces of flight

What is the function of pygostyle in birds?

Attachment of tail feathers and musculature

Name the anatomy of the forelimb = wing 

What is the “thumb” in a bird? Where is it located, and what is its function?

• Alula is the first digit of chicken

• Located on the carpometacarpal joint

• Support small stiff feather to aid in flight stability

What is the function of the humerus of birds?

Humerus is a pneumatic bone, which contains extension of cervical air sac

What bones support the primary flight feathers?

Carpal bone

What bone supports the secondary flight feathers?

Ulnar bone 

What is the third major part of wing, apart from humerus, ulna and radius

Carpometacarpus (Phalanges, metacarpus and alula)

What are the differences between the ulna and radius in birds compared to mammals?

Ulnar > Radius

What bones in the hindlimb are fused together in birds?

• Tibia and part of the tarsus fuse together = Tibiotarsus

• Some lower bones of the feet fuse = Tarsomatatarsus

From what bone downward do birds have scaly legs, and what controls the digits?

• From about the tibiotarsus downwards, the birds only got that scaly legs

• Control of digits via long tendons (Muscles located high up limb(

Name the anatomy of birds’ hindlimbs

Anatomy of foot dependent on lifestyle. What type of bird’s foot is shown in the picture below? What are its functions? In which types of birds is it typically seen?

• Type: Swimming 

• Ducks 

• Function: Paddle through the water more efficiently 

Anatomy of foot dependent on lifestyle. What type of bird’s foot is shown in the picture below? What are its functions? In which types of birds is it typically seen?

• Type: Grasping

• Predatory birds e.g. hawks 鷹

• Function: Claw-like feet help grab their prey

Anatomy of foot dependent on lifestyle. What type of bird’s foot is shown in the picture below? What are its functions? In which types of birds is it typically seen?

• Climbing 

• Woodpeckers 啄木鳥 → Climb trees 

• Sharp nails for digging into the wood + Back toes prevent the bird toppling 倒下 backward 

Anatomy of foot dependent on lifestyle. What type of bird’s foot is shown in the picture below? In which types of birds is it typically seen? What are the special features in this type of foot? 

• Type: Scratching 

• Chicken or other birds that scratch in the dirt for insect

• Feature: Have strong nails for digging into the ground 

Anatomy of foot dependent on lifestyle. What type of bird’s foot is shown in the picture below? What are its functions? In which types of birds is it typically seen?

• Type: Perching 棲息在高處

• Birds like blud jays 

• Feature: Feet with four toes, one of which is in the back 

• Function: Birds can wrap their toes on tree branches to help balance 

Anatomy of foot dependent on lifestyle. What type of bird’s foot is shown in the picture below? What are its functions? In which types of birds is it typically seen?

• Type: Running

• Emus

• Features: Three toes, al of which face forward

• Function: Help them to run quickly

What bones make up the pectoral girdle of a bird?

• Scapula 

• Clavicle 

• Coracoid 

• Keel = Sternum 

Name the anatomy of pectoral girdle 

Which bone of the pectoral girdle is fused?

Clavicle is fused to form the "wishbone" or furcula.

What is the pelvic girdle in birds?

Innominate bones (Ileum, ischium and pubis) fuse dorsally with synsacrum, making a single unit

Name the anatomy of pelvic girdle 

What is the innominate bone in birds?

• Fused bone that forms the pelvic girdle in birds

• Comprises of fused ileum, ischium and pubis

What muscles are adapted for flight in birds?

• Pectoralis (Wing depressor) 

• Supracoracoideus (Wing elevator) 

What is the function of deltoideus in birds?

Flexes shoulder and rotates wing outward

What type of muscles can be used for IM injections

Pectoral muscles

Which types of birds cannot use the pectoral muscles as a site for intramuscular (IM) injections? Why? 

• Ratites - Because ratites do not have a kneel, which there is nothing to stop our needle going right into the thoracic area 

• Nestlings (Young birds) - Because at that stage, the keel have not calcified yet = Cartilage, which is way to put a needle right through into the chest 

Why should we avoid the thigh and leg muscles for intramuscular (IM) injections in birds?

Renal portal system

→ Blood draining to hindlimb goes straightly to the kidney without going through the circulation first

= If we put certain drugs in the thighs or leg muscle, those will go straight to the kidney, potentially causing toxicity or damage.

What species of bird is this?

Canaries

What species of bird is this?

Budgies

What species of bird is this?

African grey

Cockatoo 

Lovebirds

Cockatiels

What species of bird is this?

Mynah bird

What species of bird is this?

Amazon 

What species of bird is this?

Ostriches

What species of bird is this?

Pheasants

What species of bird is this?

Finches