Becky asked: "I wonder where there might be an aviary that has hummers? That would be fascinating to study!"
NLN: I have not kept up with such information because it does not particularly interest me, but the Arizona-Sonora Desert Museum has a very well-known aviary as does [or did] the San Diego Zoo. One could learn some information such as how long after copulation is the first egg laid and if a second copulation is performed before the second egg is laid. However, information gathered in a captive environment cannot be considered absolute insofar as the birds are not making free choices but are only choosing from among the options they are offered.
Recently, a 'foraging' study was published from a study made under aviary conditions in Canada. I question how valid 'foraging' can be under these circumstances.
Becky asked: "I have another question. This one is an immediate concern. Do hummers feed at night? Or do they settle down and sleep? I ask because I've been noticing that the Cuban Tree frogs have been actually sitting in the ant moat at night ... Some of the frogs are huge! About the size of my entire hand. I'm worried that they could actually eat a hummer. They only come out at night as they have that slimmy skin and the sun will kill them. I suspect they are sitting there eating the ants that come to the feeders at night. And if that is the case, then I am okay with that. But I don't want them eating any hummers! I did catch one big frog and tossed it out in the wooded area on the west of my property, but they are smart and I suspect it may come back. If so, I'll catch him and walk down the street and dump it in another wooded area. I'm not into killing frogs (even these awful invasive Cuban frogs), so.... I just hope the hummers sleep at night instead of using the feeders. That would really make me sick to think that those frogs are laying in wait to eat one of the birds. Grrrr ...."
NLN: I have seen Rufous at the feeder at 04:00 during very cold conditions, but not at any other time. There are several published references to hummers eating after dark, especially under artificial light. However, I believe these events are exceptional rather than being regular.
Large frogs have been seen to catch hummers nectaring above ponds, etc. However, I doubt that amphibian predation is a significant source of trochilid mortality.
I know that Florida has a genuine problem with all of the exotic plants and animals that have either been released or escaped or come in with agricultural or horticultural products. There isn't much a single individual can do to alleviate the situation. Here in Louisiana, we do not yet have Cuban Tree Frogs http://wwknapp.home.mindspring.com/docs/cuban.tfrog.html
, but Greenhouse Frogs http://wwknapp.home.mindspring.com/docs/greenhouse.frog.html
and Cuban Brown Anoles http://en.wikipedia.org/wiki/Brown_Anole
have become well-established in my yard in the last 5 years. I think those lizards are kind of interesting.
Nancy L Newfield
Metairie, Louisiana USA
USDA Zone 9