Even though getting close to birds usually requires being as inconspicuous and unthreatening as possible, sometimes curiosity can work in your favor. This juvenile Yellow-crowned Night Heron definitely noticed me, and was scoping me out pretty intently. For the photographer, this is a much better situation that a bird flying away immediately, but it is still best to move slowly lest you tip the balance between curiosity and fear.
For songbirds, there is a technique called pishing, which is mimicking bird calls to attract birds. There are a few theories why it works. The “pish” sound (and various other ones) may sound like an alarm call given when a predator is noticed, or a distress call from a young bird. Whatever the exact reason, a variety of small birds, like the Yellow Warbler below, will come to investigate this sound. If other people see you doing this you may seem a bit strange, but it can be a great way to get close-up shots of birds that are otherwise hard to see.