So let’s get started.
Start by getting the overall shape of the body, head and tail, the head being the smallest can be used as a measure for the rest.
Here I would like to mention a very useful tool for getting proportions right, it’s called the 'Proportion Measure' and is included within the full eBook.
To continue make sure you sketch lightly as you will want to remove any unwanted lines later.
Next sketch in the wings then the beak and legs/feet, once you are satisfied that all these are in proportion you can start defining the bird's shape.
Next you can start on the detail but before you do so you can erase any unwanted lines, otherwise it will be difficult once all the details are in place. Now you can render in some shading, this will give it a more three dimensional appearance.