Birds Flashcards
What are 4 shared characteristics of birds and reptiles?
- Scales on beak, legs and feet
- Single occipital condyle
- Single middle ear bone
- Jaw bone of 5 fused bones
Describe the external features of the head.
Ear lobe, comb, wattle and, in the male turkey, areas on the upper beak. These enlargements are mainly for courtship and display. These areas are very highly vascularised so appear very red due to thin epidermis.
What are ceres used for?
Ceres in budgies used for sex differentiation. Crusty in females in breeding season. Male = blue, female = brown
Name and describe the 3 foot morphologies in birds.
Anisodactyl – chickens, perching, grasping prey
Zygodactyl – parrots, climbing
Palmate – ducks, swimming/paddling
Describe the avian eye.
- Large, beady eyes
- Well-developed transparent 3rd eyelid/nictating membrane
- Lower lid more mobile
- Blinking mainly by nictating membrane
- Iris usually dark – except owls and gannets
- Scleral ossicles visible on radiographs and skeletons, and gives shape to the eye
What is Marek’s disease?
A virus of birds that attacks the neurological system and cause a changes in pigmentation causing it to reduce and pupil size.
How does eye shape differ?
Flat in parrot
Globose in chicken
Tubular (useful for nocturnal sight) in owl
What is the location and role of pectin in the avian eye?
Pectin in the large posterior chamber that provides nutrients to the fluid in the tissue within.
Describe the structure of the beak.
- Replaces the lips and teeth of mammals
- Heavily keratinised epithelium overlying vascular dermis above the bone
- Rhamphotheca-keratin layer: upper part rhinotheca and lower part gnathotheca
How do waterfowl have modifications in the beak and tongue?
Lamellae present on lateral beak and tongue. Act as filter feeders to allow as much food from water to be taken into the mouth.
Casque of hornbill and pouch of pelican are other specialisations.
What are 6 functions of the feathers?
- Protect the avian skin
- Provide insulation and waterproofing
- Essential for flight
- Courtship displays
- Hearing and echolocation
- Grouse and desert species can store water in feathers and take it back to nest
Name and describe the role of the different feather types.
- Main flying feathers are primary and secondary remiges on the manus and ulna respectively.
- Rectrices/tail feathers attach to the pygostyle on the skeleton and are for braking and steering.
- Coverts feathers are feathers that give shape to the body and are found all around the body.
What are podotheca?
Podotheca are areas of the legs that are highly keratinised with no feather cover that are to withstand the forces of landing.
What is patagia?
- Wing web
- Forms leading edge of the wing
- Propatagial muscles and ligament
What are the venepuncture sites in birds? Which are best?
- Deep ulnar vein – basilic/cutaneous vein – cutaneous at elbow
- Right jugular vein
- Medial metatarsal
- Toe-nail clipping
Deep ulnar vein/basilic/cutaneous vein and right jugular, as the other 2 can be painful.
What is the function of the uropygial gland?
- Papillae secretes an oily secretion that is used to maintain feather condition and waterproofing but also acts as a barrier to bacteria and fungi.
- So few birds can skin conditions/infections
- When a bird preens and puts its head towards its tail it is releasing some of the oil from this gland to help maintain condition.
Describe the shape and features of the avian skull.
- Pyramidal in shape and brain is pushed into occipital region
- Scleral ossicles
- Mandible fits inside the maxilla to create snipping action.
- The 5 bones of the mandible are fused together caudally and articulates with the articular bone.
- Articular bone articulates with the quadrate bone, which is more upright/vertical, which gives the bird a wider gape.
How do nasal apertures vary between avian species and why?
Very large nasal apertures in the land dwelling pheasant. They are oval in shape and are very large orbits divided by a very thin septum. Gannets are water birds so have smaller apertures to reduce the amount of water that enters during diving.
What is prokinesis in birds?
- There is depression of the mandible, leading to rotation of the articular bone, causing the jugular arch to rotate and causes elevation of the maxilla.
- Craniofacial hinge joint
How does cervical vertebrae vary between avian species?
- 14 cervical vertebrae in chickens
- 25 in swans
- Neck tends to be longer in waterfowl so they can reach the uropygial glands
How does the sternum vary between avian species?
Large keeled sternum in carinates. Keeled sternum much more prominent in birds that are good at flying. Pheasants or chickens are not good fliers but can fly so do have a prominent keel. In ratite, they have much flatter, broader sternums without prominent keel, but ratites have well developed legs for running on land.
What is the notarium?
Fused thoracic vertebrae. Help the chest withstand the forces generated by the wings during flight. There is 1 free thoracic vertebrae that holds a synovial joint in front and behind it that act as a weak point in the skeleton. Can lead to kinky back, particularly in birds that grow quickly in intensive systems.
What is the synsacrum?
Very large structure that is open ventrally to allow the passage of eggs in the female. Its fusion is the fusion of a final couple of thoracic, lumbar and sacral vertebrae with the pelvis. It is responsible for supporting the pelvic girdle, which like the pectoral girdle, is entirely osseous in birds and reptiles.
Describe the avian limbs.
- Reduced manus
- Tibiotarsus and tarso-metatarsus. Some of the features of tibia, tarsus and metatarsals are incorporated. This is for extra stability in the legs to withstand landing.
What is the pygostyle?
Fusion of the last vertebrae. Rectrices tail feathers attach here.
What is the furcula?
2 clavicles are fused into the wishbone and it is known as furcula. This works during flight to help return some of the elastic energy in downbeat of the wing to help bring the wing back up using minimal amounts of muscle energy.
What is kinky back?
Ankylosing spondylolisthesis
Free synovial point in the notarium. Deterioration in vertebral points when birds grow very quickly. Degeneration due to weight gain and repetitive motion. Vertebrae slip with some degree of new fusion between the bones.
Describe the avian scapula.
Very long and thin scapula that comes considerably across the ribcage.
Describe the avian coracoid bone.
Comes off the sternum. (In mammals we have the coracoid process coming off the medial aspect of the supraglenoid tubercle).
Describe the avian humerus.
Pneumatised bone, meaning they are extensions of the airsacs that would extend into it.
Describe the avian radius and ulna.
Smaller in comparison to the ulna in birds.
How many major and minor metacarpal bones are there?
2
What is pinioning?
removing the hand like feature of the bird to render it flightless. Illegal but legal done by a vet with anaesthesia.
Describe avian bones and problems associated with them.
Cortical bone is very thin to allow for light bones for flight.
If bird breaks their humerus, it is problematic because any metalwork put in would add weight and also add infection that could be introduced into the respiratory system due to the airsacs.
Name and describe the 2 flight muscles.
Supracoracoideus – responsible for upbeat of the wing. Inserts on the dorsal humerus because its tendon runs through the triosseal canal to allow muscles that are ventral to work in opposition.
Pectorals – responsible for downbeat of the wing. Insert ventrally on the humerus.