You did a good job capturing the essence of the duckling. One thing I would suggest is to break the structure into forms. You might be able to find an anatomy breakdown of ducklings on the internet. One good exercise is to copy from what other artists have done (always give credit to the artist if you decide to post it on the internet) also, it can be very helpful to draw on top of the photograph in order to understand the structure of the animal. Then, draw around 50 ducklings from reference, then 50 more from imagination. Your visual library will thank you.
Love that light sketch of the duckling, that's the greatest start. But if I could suggest an improvement, I can see some of the underture of that duckling--why don't you caricature that bird in 10 minutes of 29-second poses, pretty please? The reason why is because, you'll get a lot better at caricaturing and exaggerating the movement of the animals and birds.
Hope it's been definitely and totally helpful.
Your duck drawing is a little hard to see. The feet are almost not there. I don't know what you are using to draw with. You could start off with an HB to block in your drawing. Once you have everything as you like, switch to a 4B. If you want a really dark pencil, use a Prismacolor Ebony which will give you jet black for really dark areas.
Also, you might want to add color which will a great deal of impact to your drawings. Get some really good quality colored pencils or maybe Arteza Fineliner pens.
Date your works so that later you can go back to compare works and see how you have progressed.
On your current work, it is a very good duck. Keep practicing.