Attached are copies of pictures I just took of my Hummingbird nest. You can see hummingbird at top. Look for her beak. The hanger turns around so the bird is facing a different way each time. How unique that the hanger has a hummingbird.
That's cute. There is a website from Cornell lab of Ornithology that has many photos of hummers nest in odd places. I tried to find it but I can't right now. I guess it didn't think that bird was real. They won't make a nest near other hummers because the other bird will kill the chicks. You should never put a feeder near a nest for that reason.
Can be? Pretty much always. They are extremely territorial and mostly do not share feeders. Some types of hummers share easier than other. Allen's hummers...forget it. They stab each other with their beaks in a second.
Our little fellas will drink out of the feeders while we are attempting to hang them. It took a while to find a feeder that kept out bees, ants and the smaller finches. It's important to clean the feeder weekly and not use harmful soaps. They seem to study us as much as we watch them!
I change my twice a week or three times when its hot. The mold and fungus can kill them. I went to Ecuador in 2012 and saw about 25 different types. That was the first time I saw many hummers sharing feeders...at the bird lodges. They still did a bit of fighting but not much.