Nectarivorous birds are those birds that rely on the nectar produced by flowering trees and shrubs. Most nectarivores are from Australia, including swift parrots, lorikeets, and honeyeaters. Avian veterinarians are still studying and learning about the nutritional requirements for maintenance, growth and reproduction of these birds and the physical adaptations necessary to digest and process their unique food sources.
Nectar is a sweet, sugar-rich liquid food source that provides lots of calories for lorikeets and other nectar eaters but is very low in amino acids, vitamins and trace minerals. Birds that ingest nectar must also rely on other food sources to meet their nutritional requirements. Pollen (composed of highly digestible proteins and diverse amino acids) as well as manna (the sugary excretions of aphids called honeydew as well as lerp, the waxy material produced by Psyllidae insects. There are several reports stating that Australia's nectarivorous birds rely on insects as the main protein source for their growing chicks. These birds have been recorded eating several species of insects including mayflies, grasshoppers, cicadas, psyllids, robber flies, lacewings, lycid beetles and moths.
Nectarivorous birds have developed a variety of adaptations to accommodate their unique diet. Their plumage tends to be tighter and glossier than other parrots to prevent feather soiling by the nectar. They have extensible brush-tipped tongues that allow for the rapid harvesting of nectar. These birds generally have lower protein requirements, lower metabolic rates and some special digestive and kidney adaptations. Some Lorikeets have a grealy reduced gizzard muscle and centrally located stream-lined openings through their gastrointestinal tracts to facilitate nectar passage. Their G.I. tracts are shorter than other parrots (because of their highly digestible diet) and these birds tend to ingest much more water than other parrots and also produce more urine. This also requires their specially adapted kidneys to resorb more water to prevent dehydration.
As researchers learn more and more about wild nectarivorous diets, veterinarians and aviculturists must apply the knowledge to our domestic nectarivores in the pet world. By fine tuning our nutritional recommendations and protocols for these birds we can improve their overall health and quality of life.
Reference: Karen Shaw Becker, DVM of Feathers Bird Clinic within the Natural Pet Animal Hospital in Bourbonnais, Illinois.