Experimental model and subject details

Rainbow lorikeets (Trichoglossus haematodus) of mixed sex were captured by canon-netting in July 2006 on the grounds of Perth Domestic Airport (Western Australia). Honeyeaters of mixed sex were captured by mist netting on the grounds of Murdoch University (Perth, Western Australia) in 2007. Singing honeyeaters (Lichenostomus virescens) and brown honeyeaters (Lichmera indistincta) were euthanized immediately upon capture. Rainbow lorikeets were held in captivity for >10 months, red wattlebirds (Anthochaera carunculata) for five months, and New Holland honeyeaters (Phylidonyris novaehollandiae) for 14 months before they were euthanized for analysis. During the period of captivity, the birds were fed a maintenance diet consisting of Wombaroo® powder (main sugar ingredient sucrose, Wombaroo Food Products, Adelaide, South Australia) supplemented with additional sucrose (∼25% m/m of total dry matter) supplied ad libitum from inverted, stoppered syringes and water ad libitum. Male Palestine sunbirds (Cinnyris osea) were captured with drop nets on the grounds of Midreshet Ben-Gurion, home of the Sede Boqer Campus of Ben-Gurion University of the Negev, Israel, in 2000–2001 and were held in captivity and fed an artificial nectar diet including 18% m/m sucrose, avian vitamin supplement, CaCO3, NaCl, KCl, and corn oil, periodically supplemented with fruit flies (Drosophila sp.) for up to three months before their tissues were analyzed. White-bellied sunbirds (Cinnyris talatala) and amethyst sunbirds (Chalcomitra amethystina) of mixed sex were mist-netted at Jan Celliers Park (Pretoria, South Africa) in May 2007 and were euthanized immediately upon capture. All birds used were adults.

Birds were euthanized by asphyxiation with CO2 (Palestine sunbirds) or halothane or isoflurane overdose (all other species) and their intestines immediately removed. Intestines were rinsed in chilled 1.02% saline and divided into three sections of approximately equal length. Each tissue section was slit longitudinally, unfolded flat, and its length and width were measured to obtain a nominal estimate of surface area. The tissue was then blotted dry, weighed and stored in liquid N2 or in a freezer at -80°C until analysis.

Animal use in this study was approved by the animal ethics committees of Murdoch University (AEC protocol R1137/05), the University of Arizona (protocol 99-103) and the University of Pretoria (AUCC 060515-012) as applicable.