Chapter 5 Parrots and related species
Psychologically, most pet birds are little different from their wild ancestors – the veterinary surgeon constitutes a potential predator so the bird is likely to exhibit a flight or fight response when handled. Exceptions to this are hand-reared parrots (or imprinted raptors and owls). However, in extremis, birds vary in their susceptibility to stress, and while some, such as the larger psittacines, can be handled relatively safely, others, such as canaries, carry a greater risk.
A great many captive-bred, hand-reared birds can be superficially examined while perched on the owner or on a freestanding perch, thereby minimizing stress. If care and patience is undertaken, then auscultation of the lungs and air sacs, plus some assessment of body condition can be achieved in this way.
Aggressive birds, or birds unused to handling, may require to be ‘towelled’ in order to examine them. Use a large towel that will cover most of the bird. Drop or place it over the bird such that the head is covered and the bird cannot see your hands. With one hand, grab the bird’s head or neck from behind so that there is control of the beak, and use the other hand to gather up the rest of the bird into the towel. Do not in any way compress the sternum, as this will seriously compromise the bird’s breathing.
Birds will attempt to mask signs of illness and so may not exhibit clinical signs until a disease course is quite advanced. It is important to observe the bird from a distance for several minutes prior to handling, as a relaxed bird is more likely to show signs of ill-health.
From Malley (1996).
Avian core body temperature often exceeds 40.5 °C and birds have a large surface area relative to body mass, which means that they must expend a great deal of energy in thermal homeostasis. Feathers act as an insulative layer but do not grow back as readily as mammalian fur, so as few as possible should be removed, should surgery be indicated.
Heat loss and, therefore, energy conservation can be reduced by placing the bird close to a heat source – vivarium heat mats are ideal for this. Place a towel or similar over the mat to prevent burns and protect the mat from fluids. Young chicks are unable to thermoregulate, so must be maintained in an incubator.
Birds are primarily uricotelic which, as in reptiles, predisposes them to gout-related problems. Blood volume is between 4.4 and 8.3 mL/100 g body weight in chickens. In some species, it can be as high as 14 mL/100 g.
|Species||Suggested volumes for cloacal administration (mL)|
|Species||Bolus volume (mL)|
If the bird is eating normally then supply its usual diet. For short-term management, recovery diets commercially available for dogs and cats (non-milk based) may be crop tubed for carnivorous, insectivorous or omnivorous birds. Dextrose can be given orally, by subcutaneous injection up to 2.5% or i.v. It is a metabolic acidifying agent and may be contraindicated in cases of metabolic acidosis. Note that most birds are diurnal and will not feed in the dark. For parrots, hand-rearing formula can be used.
A badly clipped bird is not only at increased risk of damage to itself, but such clipping may predispose to feather picking and self-mutilation. Wing clipping can be controversial but the major justification for wing clipping is that by doing so it facilitates the necessary interaction between a pet parrot and the other family members, allowing the bird to become involved with, and behave as, part of the family (or ‘flock’) rather than it be confined to its cage. However, the ideal would be that the bird is left fully flighted and controlled verbally using commands such as ‘step up’, ‘step down’, ‘leave’ and ‘no’.
|Butorphanol||0.5–4.0 mg/kg i.m. every 2–4 h|
|Carprofen||1.0–4.0 mg/kg s.c. p.o. b.i.d.|
|Ketoprofen||1.0–5.0 mg/kg i.m. b.i.d. or t.i.d.|
|Meloxicam||0.1–0.5 mg/kg s.c., p.o. s.i.d.|
|Morphine||0.1–3.0 mg/kg i.v.|
From a practical point of view, induction and maintenance with gaseous anaesthesia is of choice. Atropine can be given as pre-medication at 0.05–0.1 mg/kg s.c. This reduces mucus and counters bradycardia from vagal stimulation during surgery.
Avian respiratory anatomy means that the trachea can be ‘bypassed’ by insertion of a suitable cannula into one of the caudal air sacs (abdominal or caudal thoracic) for delivery of oxygen and anaesthetic gasses. This technique is suitable for oral or tracheal obstructions or if surgery is required at or around oral cavity. Glottal or tracheal foreign bodies or other obstructions will usually give their presence away by producing a whistling sound during the respiratory cycle. These birds are extremely liable to sudden death. The main priority is to establish a patent airway as quickly as possible, therefore the need to anaesthetize and insert an air sac tube.
Commensal bacterial numbers on the skin of birds are considered to be lower than those found on mammals. Yeasts are infrequent commensals. Malassezia not isolated from normal or self-mutilating birds (Preziosi et al 2006); in the same study, Candida albicans was isolated but significance was unclear.
Self-mutilation, like stereotypies, is a form of abnormal repetitive behaviour exhibited in captive parrots. Often psychological in origin, the alternative of an underlying causal disease should not be ruled out, either as differential diagnoses or as contributing factors. Epidemiological evidence (Garner et al 2005) points towards there being an inherited susceptibility, an increased incidence in females and a link to certain stressful environmental conditions. There are no ‘quick fixes’ and investigation is often prolonged and expensive. A methodical and holistic approach is required. This should take into account the background of the bird, its environment, its disease status and its psychological well-being.
These should not be considered a first line of action; their use should be considered once a physical or environmental problem has been reasonably ruled out or addressed. Suggested medications include:
Cere colour in budgerigars is a secondary sexual characteristic; in most sexually mature males it is a smooth, bright blue structure, while in most females it has a rougher texture, and is brown in colour. Young female light blue birds may have a pastel blue cere leading to incorrect sexing; these darken to a more normal female-type cere with maturity. Gonadal tumours may secrete inappropriate sex hormones that can lead to a change in cere colour of adult birds.