Changing Colour Mid Row
In some of my knitted bird designs, you need to change colours in the middle of the row. You can see on Barry the Puffin's head and belly that the colours change from black to cream mid-way through some of the rows in the pattern.
When you change colours in the middle of the row, you need to use a technique called intarsia. This sounds incredibly technical and terrifying but trust me, it's very simple once you get the hang of it. Basically, you knit with small balls of yarn, so you don't have to carry the colours across the back of your work, and you make sure that you twist the yarns together when you change colours, so you don't end up with little holes where the colour change happens.
(If you do end up with a hole once you have finished as you forgot to twist, don't panic and unravel your work! It can be repaired with a couple of running stitches on the wrong side of your work and no-one will be any the wiser).
So as an example, looking at Barry the Puffin's knitting pattern:
Row 13: (A) k17, (B) k14, (A) k17
A is black yarn, and B is cream yarn. So you will need two small balls of black yarn, so you don't have to carry it across the back of your cream section. Just take the big ball of black yarn in your kit, and split it into 2 balls.
You'll then work 17 knit stitches using the first black ball, then change to the cream, knit 14 stitches, and then knit another 17 stitches using the second black ball.
This tutorial video from Love Crafts explains how to do simple intarsia knitting.
In the video, the knitter is using paper bobbins to keep the yarn tidy. I have to admit, I've never done this and tend to work with just small balls of yarn. You do whichever method works for you, the knitting police aren't going to come round and give you a spot fine.