I think.... there is a parallel with sketching in astronomy. It really makes you pay attention to the features and details. Much easier with astronomy as long as you can keep following the relatively slow movement and the weather, clouds, and biting insects cooperate.
Birds, unless quite stationary or there're several in the area, like waders?, well.... Bravo to you, truly. I can sketch lifeless things and flora but my sketched horse looks like a dog and vice versa. I admire sketchers' skills. In sketching classes I was surprised though that the artists took photographs and sketched from them.