This study examined the hearing and contact calls of wild-caught Australian budgerigars (Melopsittacus undulatus) and compared these data to hearing and vocalizations in the much more extensively studied domesticated budgerigar. The spectral energy in the contact calls of both wild-caught and domesticated budgerigars falls almost exclusively in the frequency of 2-4 kHz. Absolute and masked thre...

an adult female budgerigar (melopsittacus undulatus) presented with abdominal enlargement. the condition of the bird deteriorated after needle aspiration for cytological examination. the budgerigar was euthanatized and a complete necropsy was performed. microscopic sections were prepared and stained with hematoxylin and eosin, gram staining, periodic acid-schiff (pas) and acid-fast staining. es...

Based on aerodynamic considerations, the energy use-flight speed relationship of all airborne animals and aircraft should be U-shaped. However, measures of the metabolic rate-flight speed relationship in birds have been available since Tucker's pioneering experiments with budgerigars nearly forty years ago, but this classic work remains the only study to have found a clearly U-shaped metabolic ...

The effects of kanamycin, an antibiotic of the aminoglycoside group, on the auditory sensory epithelium of the budgerigar, Melopsittacus undulatus, were examined using both scanning and transmission electron microscopes. Results show that the threshold of the auditory brainstem response increased in birds treated with kanamycin 200 mg/kg for 49 days. While the auditory sensory epithelium of the...

Microspectrophotometric (msp) studies have shown that the colour-vision system of many bird species is based on four pigments with absorption peaks in the red, green, blue and UV regions of the spectrum. The existence of a fourth pigment (UV) is the major difference between the trichromacy of humans and the tetrachromacy of such birds, and recent studies have shown that it may play a determinin...