Budgerigar

Budgerigar（圖片來源：Jim Bendon from Karratha, Australia，採用 CC BY-SA 2.0 授權）

The budgerigar (Melopsittacus undulatus) is a small parrot species native to the interior regions of Australia. In the wild, individuals typically possess bright green and yellow plumage, with the back and wings covered in black, wave-like markings that give rise to the name “budgerigar.” Wild populations are usually smaller in body size, with adults measuring about 18 cm in length and weighing only 30 to 40 grams. Despite their small size, their agile flight ability and strong social behavior have allowed them to survive for more than five million years in the arid grasslands and shrublands of Australia. In nature, budgerigars are highly gregarious birds, commonly gathering in flocks ranging from dozens to thousands of individuals. These flocks often migrate across large areas following seasonal rainfall and the availability of ripening grass seeds.

Their diet in the wild mainly consists of grass seeds, especially those from Australian plants of the genus Spinifex as well as various members of the grass family. Because these foods contain little moisture, budgerigars have a strong dependence on water sources. Large flocks often gather at waterholes during dawn and dusk to drink. This regular pattern of behavior enables them to cope with the harsh conditions of arid environments.

Reproduction in the wild is not tied to a fixed season. Instead, breeding begins rapidly when environmental conditions become favorable, particularly after rainfall when grass seeds become abundant. Budgerigars typically nest in tree hollows, hollow stumps, or crevices in fallen logs. The female incubates the eggs while the male performs most of the foraging and provides food for the female and chicks.

Large flocks sometimes feed on cultivated grain fields, and for this reason budgerigars have occasionally been regarded as agricultural pests in Australia. Since their introduction to Europe during the nineteenth century, they have been bred in captivity for many generations. Selective breeding has produced dozens of plumage color varieties, including blue, white, gray, violet, and yellow combinations, as well as crested varieties. These traits have made budgerigars one of the most popular birds in the global pet trade.

Flock of budgerigars in the Australian wild（圖片來源：Jim Bendon from Karratha, Australia，採用 CC BY-SA 2.0 授權）

Captive-bred blue budgerigar（圖片來源：H. Zell，採用 CC BY-SA 3.0 授權）

Housing Requirements in Captivity

In a household environment, budgerigars require a space that is both secure and large enough for movement. A basic cage should provide at least 45 cm of space in each dimension, and the spacing between cage bars should not exceed 1.5 cm to prevent birds from attempting to squeeze through and becoming trapped. If multiple birds are kept together, the cage size must increase accordingly; otherwise aggression and psychological stress may occur. Because budgerigars are active fliers, cages should ideally offer wide horizontal flight space rather than tall and narrow structures.

Perches should be varied in thickness, material, and height. Such variation helps strengthen the muscles of the feet and reduces the risk of foot disorders caused by gripping a single perch diameter for extended periods. Perches made from excessively rough artificial materials should be avoided because they can damage the feet. Natural wooden perches are generally preferable.

Toys and chewable objects should also be placed in the cage. Safe wooden blocks, paper items, or specially designed bird toys can provide mental stimulation and help prevent abnormal behaviors such as feather plucking caused by boredom.

Lighting plays an essential role in budgerigar health. Ultraviolet light from sunlight enables the synthesis of vitamin D3, which indirectly supports calcium absorption. When natural sunlight is unavailable, specialized avian UVB lamps can be used to provide 10 to 12 hours of light each day. The cage should be placed in a well-ventilated and bright location that avoids both intense direct sunlight and strong drafts. A comfortable temperature range between 18 and 27°C is recommended.

Environmental cleanliness must also be maintained. The cage floor can be lined with newspaper or specialized bedding material to facilitate daily replacement. Water bowls, food dishes, and perches should be cleaned regularly to prevent the growth of bacteria and fungi. If a safe outdoor flight area or a spacious indoor flight environment can be provided, the bird's physical condition and psychological well-being will improve significantly.

Feeding Conditions

Under captive conditions, a budgerigar's diet should balance nutritional completeness with variety. Although these birds are naturally granivorous, diets consisting solely of seeds often lead to nutritional imbalances, including deficiencies of vitamin A, calcium, and essential amino acids. High-quality formulated pellets are therefore recommended as the primary component of the diet, making up approximately 60 to 70 percent of daily intake. The remainder may consist of small amounts of seed mixtures, fresh vegetables, and fruit.

Commonly suitable vegetables and fruits include carrots, sweet peppers, broccoli, peas, spinach, papaya, blueberries, and cantaloupe. These foods provide additional vitamins and antioxidants. However, fruits contain relatively high levels of sugar and should be limited to less than ten percent of the total diet. Foods that must be avoided include avocado, chocolate, caffeine, alcohol, onions, and heavily salted foods, as these substances are toxic to parrots.

Among seeds, millet and foxtail millet are particularly favored by budgerigars and are often used as treats or training rewards. However, excessive amounts should be avoided because they may lead to obesity and fatty liver disease. Fresh, clean drinking water should be provided every day. Bottled water or boiled dechlorinated water is suitable, and water containers should be cleaned and refilled daily. Budgerigars also enjoy bathing in shallow water dishes, which can help maintain feather condition and provide behavioral enrichment.

When feeding, it is best to place pellets and fresh foods in separate containers to maintain cleanliness. Any remaining fresh food should be removed within several hours to prevent spoilage or fermentation. If owners wish to build a closer relationship with their birds, small portions of grains or vegetables can be offered by hand as rewards. This approach can increase trust and help birds become more accustomed to human interaction.

Breeding Conditions

Breeding budgerigars in a household setting requires careful consideration. In the wild, they reproduce quickly when environmental conditions are suitable. A female typically lays between four and eight eggs per clutch, with an incubation period of about 18 to 21 days. The chicks develop feathers and begin to become independent at around five weeks of age. Without proper control, excessive breeding in captivity can place significant strain on both the birds' health and the owner's ability to care for them.

If breeding is planned, the parent birds should first be confirmed to be healthy and unrelated in order to reduce the risk of inherited disorders. A dedicated nest box should be installed in the cage, lined with wood shavings or pine chips to maintain dryness and cleanliness. During incubation, the female's activity decreases substantially and she remains in the nest box for most of the time, while the male performs the majority of foraging and feeding duties. Disturbance should be minimized during this period to avoid nest abandonment or aggressive behavior.

Common issues during breeding include fighting between females competing for nest boxes, chick mortality caused by overcrowding or genetic defects, and developmental problems such as splayed legs in chicks. Providing additional nest boxes and carefully selecting healthy breeding pairs can help reduce these risks.

In general, hand-rearing very young chicks is not recommended. However, if a female abandons the chicks or if there are more chicks than she can adequately care for, manual feeding may become necessary. Because budgerigars are small birds, hand-feeding carries a relatively high level of difficulty and risk. Specialized chick formulas and feeding equipment must be used, and strict hygiene and appropriate temperature conditions must be maintained. If experience is lacking, assistance from an avian veterinarian or an experienced breeder is strongly recommended. Unless there is a clear plan and sufficient expertise, allowing pet birds to breed casually is not advisable.

Preventing Invasive Spread

Budgerigars originate from Australia and are widely kept as pets around the world. However, if they are abandoned, intentionally released, or escape in non-native regions, they may pose ecological or agricultural risks. These birds are capable of reproducing rapidly, and their potential to establish feral populations should not be underestimated. In the past, feral populations have been recorded in the state of Florida in the United States. Although these populations gradually declined due to competition with other bird species for nesting sites, their presence demonstrated that budgerigars can establish themselves outside their native range.

For this reason, owners must follow the principle of never abandoning or releasing pet birds into the wild. If continued care is no longer possible, the bird should be transferred to a legitimate animal shelter or a responsible new owner rather than being released outdoors. Parrots are intelligent birds with strong social bonds, and abandonment can cause severe psychological distress. Responsible ownership requires a commitment to the animal's welfare for its entire life. Keeping a pet should never be an impulsive decision that disregards the value of living beings.

Author: Shui-Ye You