I just looked up wattlebirds, and they appear to be nectar feeders, like our hummingbirds. How large are they? I know they aren't related below the level of the family Aves, but it looks like they have some convergent evolution for filling very similar niches. In fact, the Wikipedia article even mentions convergent evolution, which is a rather rare thing for them to do.
Can they hover at flowers and fly backwards like our hummingbirds seem to do?
http://en.wikipedia.org/wiki/Hummingbird#Superficially_similar_birds
The fierceness with which hummingbirds defend their territories may be why the Aztec War Deity is sometimes represented as a hummingbird; as well a why so much Aztec violence imagery is centered around the poor birdies.
Hummings have the highest metabolic rate of any endothermic organism - and they can still live a decade or more, which is unusual for animals with very high metabolisms.
Hummingbirds are capable of slowing their metabolism at night or any time food is not readily available, entering a
hibernation-like, deep sleep state known as
torpor needed to prevent energy reserves from falling to a critical level. During nighttime torpor,
body temperature falls from 40oC to 18oC,
[21] with
heart and
breathing rates both slowed dramatically (heart rate to roughly 50 to 180 beats per minute from its daytime rate of higher than 1000).
[22]
During torpor, to prevent
dehydration, the
kidney glomerular filtration rate ceases, preserving needed compounds like glucose as a source of fuel, water and nutrients.
[19] Further, body mass declines throughout nocturnal torpor at a rate of 0.04 g per hour, amounting to about 10% of weight loss each night.
[19] The circulating
hormone,
corticosterone, is one signal that arouses a hummingbird from torpor.
[23]
Use and duration of torpor vary among hummingbird species and are affected by whether a dominant bird defends territory, with non-territorial subordinate birds having longer periods of torpor.
[24]