Reddit reviews NEKTON Nectar Feeders for Birds, Holds Up to 40ml

What state are you in? What's wrong with the hummingbird? What's the cage setup look like?

Their diet is not primarily nectar, they are insectivores. The nectar is just an extra energy boost so they may keep hunting insects.

Rehabbers have a few ways of feeding them: Nektar Plus, Roudybush nectars, and homemade nectar. My preferences are the former two. Roudybush sells nectars for all stages of life. At this point you'll only be getting adults, and they require nectar 3. The "3" refers to 3% protein. Juveniles get nectar 9 and nestlings get nectar 15. This must be made 3mL water:1g powder ratio. Nektar Plus can be purchased on Amazon. It's a lot more expensive, but it's a little more elemental, meaning the hummingbirds can digest it more easily which helps if they're starving. This must be made in a 5.5:1 ratio by volume. This stuff goes bad very quickly, like in hours if it's exposed to direct sunlight, so keep an eye on it and replace it if it stats to lose its color. If you have nothing, you can use a 4:1 water:sugar mix and order the nectar. Since it's monday, you'll get it in a few days if you order it with fast shipping. Or you can ask another rehab center for some nectar. A tablespoon will go a long way, so they don't need much.

Hummingbirds should be fed in either a Nektar Plus feeder or a red-tipped syringe. They should eat between 4mL (if they're depressed and not moving for most of the day) and 12mL (if they're flying). Significant changes in feeding habits indicate depression, stress, and/or impending death.

Don't do BCS or examine them like you would a normal bird. Hummingbirds only require a weight and a visual confirmation of injury/illness. They are extremely prone to stress and handling them will kill them if you're not careful. They have very different personalities and will tolerate humans differently. They are too small for radiographs so don't bother. Hydration checks are also useless, and don't give them any SQ fluids.

Wing injuries: This is the most common thing I see. A broken wing that results in the bird holding the wing improperly will almost never recover. Almost every wing injury is at the shoulder and that's difficult to fix on even large birds. If there's no improvement in 2 weeks (either in range of motion or how the bird holds the wing), then euthanize. If both wings seem to be broken, it might be a keel or shoulder injury. This can heal with time and a limited cage size (1ftx2ftx1ft is what I use), but it will take 6-8 weeks.

Head injuries: Some pain meds mixed into the food is the only thing that can be done. If they're twisting around on the ground you will probably want to euthanize, as they won't be able to drink at all. If they have a slight head tilt or are off-balance, they'll need to be constantly monitored or hand-fed to ensure they get enough nutrition in them.

Cat attack: Clavamox at 250mg/kg (or about .1mL for a 2.5g hummer) added to food is best. Can also use Baytril at 40mg/kg. Never give this to them all at once, it must be added to the amount of food they consume in 1 day.