The diet of the New Holland honeyeater, Phylidonyris novaehollandiae

Abstract

New Holland honeyeaters collect nectar, manna or honeydew for energy and hawk small flying insects for protein. The insects taken were usually Diptera and Hymenoptera weighing 0.7 mg dry weight or less. Net rates of energy gain from hawking small flying insects were usually less than 20 J min~' and sometimes negative and insufficient to meet the bird's daily energy requirements. Those from feeding on nectar, manna or honeydew were usually above40J min~^ andoftenabove400J min~^ atdawn and the birds depended on these carbohydrates for energy. Nectar, manna and honeydew contained negligible amounts of protein, and the birds used small flying insects as sources of protein, and presumably other nutrients. Given that carbohydrate resources supply better rates of energy gain than insects. New Holland honeyeaters should collect their energy requirements from carbohydrates and only collect sufficient insects to satisfy their protein requirements. Estimates of the food intakes of both non-breeding and breedig birds showed that they did this. Non-breeding New Holland honeyeaters collected from 72 to 125 (mean 92) kJ of carbohydrates per day and 17 to 58 (mean 31) mg of protein per day. These meet the daily energy (75 kJ) and protein (20 mg) requirements of the birds. Breedig birds collected more carbohydrates and more insects, but in proportion to their increased energy and protein requirements respectively.

Nectar as food for birds: the physiological consequences of drinking dilute sugar solutions

“…Adult nectarivorous birds appear to have unusually low daily protein requirements compared with other bird species (around 1.5% of daily diet on a dry mass basis, Paton 1982, Brice and Grau 1991, Brice 1992, Roxburgh and Pinshow 2000, Van Tets and Nicolson 2000. Adult Anna's hummingbirds Calypte anna can survive for long periods (up to 10 days) with no protein intake (Brice and Grau 1991).…”

“…Despite low daily protein requirements, nectarivorous birds are unable to meet their nitrogen requirements on an exclusively nectar diet (Martı´nez del Rio 1994). Other nitrogen sources include insects (Paton 1982, Brice 1992 and pollen (Wooller et al 1988, Van Tets andNicolson 2000). However, net rates of energy gain from hawking insects are small (usually <20 J/min, certainly lower than energy gain from nectar feeding) and sometimes negative (Paton 1982).…”

“…Taste preferences and digestive limitations, such as differences in the time required to process or assimilate sugars, are affected by diet concentration, so that neither composition nor concentration can be considered independently. Bird-dispersed fruits resemble the nectars of passerine-pollinated (Percival 1965;Skead 1967;Hainsworth and Wolf 1972a, b;Hainsworth 1973Hainsworth , 1974Baker 1975;Gill and Wolf 1975a, b;Stiles 1975;Wolf 1975;Hainsworth and Wolf 1976;Wolf et al 1976;Cruden and Toledo 1977;Hainsworth 1977;Bolten and Feinsinger 1978;Bond and Brown 1979;Brown and Kodric-Brown 1979;Waser 1979;Pyke 1980;Corbet and Willmer 1981;Frost and Frost 1981;Pyke and Waser 1981;Baker and Baker 1982a, b;Feinsinger et al 1982;Paton 1982;Collins 1983;Cruden et al 1983;Heyneman 1983;Wiens et al 1983;Freeman et al 1984;Gottsberger et al 1984;Lammers and Freeman 1986;Buys 1987;Craig and Stewart 1988;Elisens and Freeman 1988;Moncur and Boland 1989;Arizmendi and Ornelas 1990;Freeman et al 1991;Stiles and Freeman 1993;van Wyk et al 1993;Johnson and Bond 1994;K...…”

“…Other nitrogen sources include insects (Paton 1982, Brice 1992 and pollen (Wooller et al 1988, Van Tets andNicolson 2000). However, net rates of energy gain from hawking insects are small (usually <20 J/min, certainly lower than energy gain from nectar feeding) and sometimes negative (Paton 1982). Therefore, provided that nectar is available, it would be expected that birds would not invest more time on insect feeding than is required to meet daily nitrogen requirements (Roxburgh and Pinshow 2000), contributing to strong selection for low nitrogen requirements.…”

Salt intake and regulation in two passerine nectar drinkers: white-bellied sunbirds and New Holland honeyeaters

“…We assume similar values for the New Holland honeyeaters, although we know little about the electrolyte concentrations of Australian nectars. Therefore, if we can assume that their voluntary salt intake in the laboratory reflects sodium requirements, it is likely that arthropods, in addition to being an important source of protein (Paton 1982;Stiles 1995), are also a source of electrolytes for avian nectarivores.…”