First, no need to use the red nectar. Some think it is harmful to the hummingbirds and there is no really is no reason for it at all, especially since most feeders have red in them. Cane sugar is the best to use, one part sugar to 4 parts water.

Sometimes they move around, perhaps some of their favorite flowers just opened up a few yards away, etc... Only thing I can think of that you could have done wrong is to not change the sugar water enough. Really hot weather and a feeder in direct sun could need to be changed every one or two days. Cooler temps and shade could go longer. Besides the fact that spoiled sugar water could harm the hummingbirds, I have heard that at some point they will not drink from the feeder.

Best to change it more often rather than longer. Besides the hummers getting sick or rejecting the feeder, let it go too long and you will have mold and it will take more time to clean.

Ken

Ken is right.

My feeders here are turning cloudy much sooner than any previous year. I have to clean them up and re-fill on the third day.

Be patient for your hummers. My first two years I didn't have many hummers. Your on the coast and will have lots of hummers. They will be back.