Scientific Name: Malurus splendens
Family: Maluridae
Order: Passeriformes
Introduction:
The Splendid fairy - wren inhabits the states of Australia from south Western Australia to central western N.SW and southwest Queensland. Their diet is mainly insectivorous however it is supplemented by small amount of flowers, fruit and seeds.
The Splendid Fairy - wren has a lifespan of approximately 6 years and is about 14cm in length. The Splendid fairy - wren male has deep blue back wings,chest and tail and bright blue ear coverts and blue forehead during breeding season exhibiting a high degree of sexual dimorphism. Out of breeding season the male is brown with blue in the wings and tail which is very similar to the female.
Traits & Behavioural Patterns :
The Splendid fairy - wren “hop search” their food from the ground or in shrubs less than 2m from the ground. When threatened they use a ‘rodent - run’ display to distract predators from their nests of chicks. This display involves a continuous alarm call and the bird will low its head, neck and tail whilst fluffing its feathers and holding out both wings.
The Breeding Cycle:
Breeding season for the Splendid fairy - wren occurs from late August to January. The female will make her small dome shape nest structure using woven grasses and spider webs which she will conceal in thick and often thorny vegetation. The female creates a small nest which often bends their long tail during incubation. The female can lay 1-2 clutches each season of up to 4 dull white eggs with brown/red spots. She will incubate her eggs for 14 - 15 days and after hatching all group members will feed the nestlings for up to two weeks until they are able to fledge. The nestlings are often a different diet of larger pieces such as grasshoppers & caterpillars.
When it comes to mating in this time the pair bond for life but regularly mate with other individuals and even help raise their young. The Splendid fairy - wren has a reputation for being very unfaithful and exhibit a very polygynandrous (promiscuous) mating system. It has been known that males will also remove semen from the female and replace with their own. During the breeding season the males display several courtships. One display involves the flaring of the blue ear tufts by erecting the
feathers called “face fanning”. Another display involves the male extending his neck and erecting his head feathers, flying and tilting his body from horizontal to vertical. He will also rapidly beat his wings so he is able to descend slowly and spring upwards after landing on the ground. This courtship is called the “sea horse flight” which is named due to the similarity of movements by seahorses.
Male Splendid Fairy - wrens have habit during mating season of plucking petals which contrast with their plumage (usually pink & purple) which is apart of a courtship display in their territory or another territory. Males also show petals to other females outside of breeding season in other territories to advertise themselves. This petal - carrying behaviour may also be a way to reinforce pair bonding and also a way for extra males to gain copulation with a female.
How The Respiratory System Is Different In Birds:
When comparing a birds respiratory system with a mammals there is a significant difference in the structure of the system. Birds are very busy animals and require high
Energy foods and have higher metabolic rates that demand bigger oxygen levels.
A bird have a slower respiratory rate and requires two respiratory cycles (inspiration, expiration, inspiration, expiration) whereas mammals only require one cycle. This means the birds respiratory system can be more efficient than a mammals
however toxins can also be transferred more quickly.
Humans also have an alveoli whereas birds have a parabronchi.
(as shown in the diagram below) The alveoliin humans is the grape-like clusters which are sites for gas exchange surrounded by capillary networks. The oxygen diffuses from the alveoli into blood capillaries and carbon dioxide diffuses from the blood capillaries into the alveoli. A human’s air flows into two directions from our nostrils through the trachea to the alveoli and then back again through the same ducts. Therefore the air breathed first into the alveoli is over used having given up most of the oxygen before the last exhalation.
Birds have a respiratory system that moves air in one direction which enables their high activity levels and the air sacs also help regulate body temperature providing a mechanism to dissipate excess body heat. Unlike humans birds do not have sweat glands and rely on the air sacs for thermoregulation. During expiration, air is forced from both air sac groups from the air sacs contracting. Air flows one way through the parabronchi during inspiration and expiration. Air from the posterior thoracic sacs move through the parabronchi whilst air from the anterior thoracic sacs move into the primary bronchi and trachea and then out of the body.
Birds have up to 9 air sacs which include:
· Two cervical sacs
· Two anterior thoracic sacs
· Two posterior thoracic sacs
· Two abdominal sacs
· One interclavicular sac
These 9 air sacs have thin walls and few blood vessels which do not play a role in gas exchange but rather act like a “bellow” to ventilate the lungs and to keep the air moving in one direction. These air sacs branch from the lungs into parts of the body cavities and bones. Birds also do not have a diaphragm unlike mammals. Which means the air is moved in and out of the respiratory system through pressure changes in these air sacs. Chest muscles cause the sternum to be pushed outwards creating negative pressure in the air sacs causing the air to enter the respiratory system. Certain muscles need to contract to increase pressure on the air sacs and push the air out as expiration is not done passively.
The Internal Structure Of Birds:
A birds structure is made to facilitate flight. The skeletal system of a bird weighs less than its feathers to help with flight and the birds major limb bones are hallow with internal struts for support. Therefore the skeleton structure can make up for only 7% of total body weight (as found in Eagles). The bones are a honeycomb like structure and the wing is similar to the human arm made up of a humorous and two lower limb bones with digits. Birds have a large cranium and an upper jaw AND lower jaw that moves when the bird opens its mouth. Depending on the length of the neck the vertebrae consists of 39 to 63. Bones are fused to make a firmer skeleton to withstand the large pressure of wing motions & stress. The two collar bones in a bone are fused and the ribcage has additional sideways growths which help strengthen the ribcage. Skeletal weight is also reduced as birds do not have teeth, heavy jaw bones nor long tail bones. Birds also have an oil gland at the base of the tail which helps maintain its feathers.
Birds have an extension of the breastbone (sternum) called a keel which acts as an anchor to which a bird’s wing muscles attach that provides appropriate leverage for flight. Flightless birds do not have a keel. Birds have a somewhat of 175 muscles that control its body movements. The largest muscle which can weight up to 15-25% of the birds body weight is the pectoralis which originates from the breastbone to the head of the upper arm bone called the humerus. The large, stout bones that connect the sternum with the shoulder are called the coracoid. Birds have a compact body which is required to transfer adequate wing energy to the centre of the body mass.
A bird’s heart is similar to a mammals and has four chambers which are divided into two atria and two ventricles. The atria is the receiving vessel of blood from the end of its journey and the ventricles pump the blood off to its journey again. The heartbeat can vary from 60 per minute (in humming birds) to more than 1000 per minutes in an Ostrich. A bird’s heart is larger than that of a mammals.
The respiratory system of a bird is very different to mammals as the air flow is in one direction enabling their high activity. It can consist of up to 9 air sacs which branch from the lungs into parts of the body cavities and bones. These air sacs also aid in regulating body temperature which can sometimes reach up to 46 degrees Celsius.
Birds no not have sweat glands so they will often ‘pant’ to cool their body down.
Birds have a crop which is situated under the neck which is composed of layers of muscle tissue which holds and softens the food until it is ready to be passed through the gizzard. Birds also lack the soft palate that allows swallowing and need to tilt
their head back to allow it to the reach the top of the Oesophagus. The gizzard is a tough tissue structure containing roughage that grinds the birds food into a pulp, ready to be passed through the intestine. The kidney and liver filter out toxins and waste and then passed from the kidney through a tube called the ureter which connects to the cloaca. The cloacais the single opening for all urinary, intestinal and reproductive tracts.
Bird’s have strong feet and legs which are covered in tougher skin than the rest of the bird’s body. The upper leg bone, the femur,which is often hidden connects to the lower leg bone which is long and composed of a well built tibiotarsus and thinner splinter - like fibula. The tibiotarsus then connects to the tarsometarsus that connects the feet. Most birds have four toes but it does depend on the species. Emus have three toes and ostriches have two. Flightless birds have large heavy leg bones that help them escape danger where as other birds such as a rooster may have a fifth toe that has become a defensive spur. The structure of a bird’s foot depends on what is used for such as prey, propelling, grasping and climbing.
Written By: Cushla TISOVN Student - The Advanced Certificate In Avian Studies
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