Realistic bird drawings will require creating many bird sketches to understand its form and the unique challenges it brings. This section will cover drawing a few common bird species and what I did to make it doable. I envision that this will work for you as well.
Birds play a huge role in human society. In culture, religion, and mythology, birds serve as some sort of messenger or symbol of divinity (good or bad). These animals are seen portrayed through the earliest cave paintings to the most recent drawings.
Even flight technologies, like the airplane, are based on the understanding how the wings work. On a lesser level, artists seeking to learn realistic bird drawings should seek a similar mindset to understand as much of the form as possible.
The realistic bird drawings here shows birds with unique forms. For example, positions of the feet on a duck, the broad wings on a turkey, the large eyes of an owl, etc. The list goes on and on. Each of these unique characteristics has its own way of being drawn.
When starting out, get familiar with the drawing tools available. Details like the feathers in these guides will use the smudge tool extensively for both roughing in the shape of the feathers as well as defining the individual textures on it.
It's a very powerful tool that should not be ignored. Adding on to that, layer management through locking it is necessary to keep all the details contained within the boundaries of the shape of the bird. For now, pick a favorite bird to begin its lesson!
As mentioned, these birds are rewarding as well as challenging to draw in their own right. There has never been a time where I got bored learning realistic bird drawings of a specific type.
I am sure you will have a similar experience figuring out what you need to do to make a bird drawing successful. Furthermore, what I have learned here can be used for other drawings.
I know stuff like wings can cater to a whole different bunch of fantasy drawings involving angels. Anything else can be used for mythical creatures like griffins or dragons. There are a lot of options out there to apply the knowledge gained.
Regardless, the final results of any realistic bird drawings are based on how much effort is put into the learning about the form, detailing out the form with the right tools, and understanding how light sources work.