Re: Ornithologists, what happened here?
I don't know Xtraham, cold nectar related hypothermia just doesn't sound right, especially since the incident occured during the evening rather than the morning and that JB stated that the nectar was between 75 and 80 degrees. I read somewhere that hummingbirds are at risk for 'temporary' cold nectar related hypothermia primarily in the morning.
For those new to hummers, they eat bugs for protein & nutrition; the nectar is what 'fuels' their ridiculously fast metabolism. I've read that they make it through the night by feeding heavily on nectar at dusk and that they also go into a kind of semi-hibernation state while they sleep (metabolism & heart rate slow wayyyy down). Still, upon awakening.their 'fuel tank' is low, which is why they swarm to nectar first thing in the morning.
If it was a cold night they would need the nectar even more upon awakening since they burned more 'fuel' during the night to keep warm (in spite of the semi-hibernation state). The combination of an even more depleted fuel tank upon awakening, the increased need for nectar to keep warm because of the cold air temp, and the fact that the nectar is going to be coldest first thing in the morning is what would provide the greatest risk of temporary 'cold-nectar' hummer hypothermia. The cold nectar is gonna cool the birds core temperature a bit before it can metabolize it into fuel to keep warm.
After a cold night I don't think you'd need to 'warm' (even tepid) the nectar before the birds hit it in the morning, I bet room temp would be just fine. Still, bringing in the feeders at night & putting them back out in the morning before they feed wouldn't be very practical for most people (impossible for me). One suggestion I've heard is to take the perches off the feeders if it's gonna be a cold night. With no perches they have to hover in order to drink, which will heat them up and help offset the effect of the cold nectar temperature.
I've read a fair bit about hummers, but am certainly no ornithologist, so I'd be guessing what happened with your birds, JB. Given that 4 dropped at once, the fermented nectar theory would have seemed to make alot of sense, except that you had just put in fresh nectar. Having 4 drop at once from collisions seems like it would be possible but unlikely. My guess would be either a) the exhaustion theory, i.e., they were expending alot of energy to get at the nectar but weren't able to or b) one of the feeders might have been 'contaminated'. Probably wouldn't take long for that to happen if it was really hot. Were the downed birds all under 1 particular bottle? How often do you clean the feeders & bottles? Do you boil the water before you mix in the sugar?
I suspect I don't have quite as many hummers as JB, but I get ALOT. I was going through just under 2 quarts of nectar a day during mid-late summer. Impossible to count the number of hummers I've got because it looks like a beehive at times. Best I could do was estimate 20+ hummers buzzing two feeders I have hanging about 6 feet apart. I'm sure there were more in the trees I couldn't see. I keep a third feeder around a corner of the house, out of sight of the other 2 so one bird can't 'guard' all of them at once. It got to the point where it was such a pain to keep the feeders full I modified 2 of my feeders so that I could use a 2 liter soda bottle with them instead of the 30 ounce bottle they came with.
They can be aggressive little buggers, but I've seen 7 birds feeding off of a 4 port feeder at the same time. Two hummers were simultaneously drinking from a 'flower' at each of 3 ports, with a single bird at the fourth one. It's neat to see two birds drinking from the one flower hole at the same time. Wonder if it might have something to do with being from the same family or just that their hunger has overridden their territorialism at that point (happens most when I have only 1 feeder out 'cause it's early in the year or I'm cleaning/ filling the other feeder).
Here are some of the things I've read from various sources:
Homemade nectar (1 part sugar to 4 parts water) is actually better for hummers than the store bought kind because it doesn't have food coloring. Colored nectar doesn't do anything to help draw hummers, and the food coloring can be bad for them. Boil the water vigorously for 3-5 minutes before mixing in the sugar. Sterilizes the water which probably helps the nectar keep longer, and makes disolving the sugar very easy. I have well water, and sometimes when it smells kind of funky I use filtered water rather than water directly from the tap (I've got a gallon Pure water filter dispenser that I use for myself instead of buying bottled water).
The nectar will keep in the fridge for a week or even a little longer, but it's recommended that you change the nectar in the feeder if it starts to become cloudy or you see anything growing on the inside of the bottle. How long it lasts is probably directly related to how hot it is & how much direct sunlight it gets each day. Most sources recommend changing every 3 days, but unless I get very hot weather, I've had no problem with going 5 or 6 days between changes.
Wash your feeder(s) regularly. Use a bottle brush where needed. Get one of those 'mini' brushes to clean out the feeder port holes.
Never use an artificial sweetener or honey to make nectar. These can kill the birds.
You can make your nectar stronger than 1 part sugar to 4 parts water, but the hummers will drink less of it. This can be a good thing if you're going to be away for a bit & can't refill the feeders as quickly as they would ordinarily need it. The 1-4 ratio is what is usually recomended as being closest to natural nectar, but in reality the strength of nectar varies in different flowers from which the birds feed. Bottom line is that they need X amount of sugar calories from nectar for fuel. If the nectar mix has a higher sugar ratio, they'll need less nectar to get the same amount of calories than from a mix with a lower sugar ratio. I'd never go less than 1 part sugar to 4 parts water, and probably no stronger than 1 part sugar to 2 parts water (I think that's about the range of natural nectar in different flowers; wish I had bookmarked the site where I read the differences in nectar strength from different flowers).
Bees & wasps are supposedly more attracted to yellow on your feeder than to red. Don't know why and can' t personally confirm this, but I did read it somewhere.
JB, sounds like you might be oversaturated with hummers given your feeder set-up. Next year you may want to think about going to a 1-3 sugar-water mix to cut down on 'demand' a bit and/ or setting up a feeder or two in a seperate area to allow more efficient feeding. Just something to think about given that you've been doing this about twice as long as me, and are obviously very successful.
