So under the eaves of houses are ideal sites for them. The Museum cannot advise you to violate the Migratory Bird Treaty Act, which protects all native birds of North America. A mixture of one part sugar to four parts of water is sufficient. Red food coloring is not necessary as long as the feeder's orifice is contrastingly colored. Wash the feeder with soap and hot water every few days.
Hummingbirds feed heavily on tiny insects as well as nectar.
I'm seeing so many more crows and ravens than I used to. Yes, both these species have increased since the 1980s. The crow in particular has spread its range into metropolitan San Diego, where it was absent before about 1985. San Diego is right at the southern edge of the crow's normal range. The raven always occurred here but has increased.