I have never been a real photographer. The last time I owned a camera (not phone) was 10 years ago. Since smartphone became popular, I have always preferred using smartphones because it's easier to carry around.
However, occasionally I do wish I had better gears, mostly lens. I recently moved from a big city to somewhere with more wildlifes, and I'm interested in shooting some bird photos, so I guess I need some good lens with zoom factor. Are there any phone accessories that will allow me to do this?
There are, but because you're adding another optical system on top of another optical system, it's never going to be quite as good. Top it off, these adapted monoculars (which is what they are) tend to be on the cheaper end, so there's going to be a lot more optical defects that'll really show up in a photo.
You can see an example of the best case scenario here, with a high quality Swarvoski spotting scope: http://www.birdchick.com/digiscoping There's lowered contrast and massive purple fringing even at the lower web resolution.