This investigation was conducted on 30 adult, male and female budgerigars. The thyroid and parathyroid glands adhere to each other on both sides of the body and are surrounded by a common connective tissue capsule. The glandular "cluster" on the right side was cranial and dorsal in relation to that on the left. The thyroid glands were most often supplied with blood by the following glandular ar...

0

Understanding the mechanistic bases of natural color diversity can provide insight into its evolution and inspiration for biomimetic optical structures. Metazoans can be colored by absorption of light from pigments or by scattering of light from biophotonic nanostructures, and these mechanisms have largely been treated as distinct. However, the interactions between them have rarely been examine...

An increasing number of studies indicate that not only females but also males can be selective when choosing a mate. In species exhibiting male or mutual mate choice, females may benefit from being attractive. While male attractiveness is often positively influenced by higher plasma levels of the androgenic hormone testosterone, it has been shown that testosterone can masculinise female behavio...

Male and female juvenile budgerigars, Melopsittacus undulatus, were allowed to observe a conspecific demonstrator using its beak to remove one of two distinctively coloured objects (i.e. a blue and a black stopper) from a hole in the lid of a box and eating seed from within. Both objects could be removed by either pulling up or pushing down. When subsequently allowed access to both stoppers, an...

The isolation and characterization of two avian polyomaviruses, from chicken (BFDV-2) and a parrot (BFDV-3), is reported. Both isolates are closely related to the non-mammalian polyomavirus budgerigar fledgling disease virus (BFDV) isolated from budgerigars (now called BFDV-1), and all three viral genomes are shown to have the same basic size of 4981 bp. A 151 bp insertion was, however, observe...