Contrasting or complimentary colors (same) refers to the colors opposite one another in the Hue wheel, like Blue-Yellow, Green-Magenta and Cyan-Red. Whenever they are used together in an image, they bring out high impact, boldness, high color contrast. Colors that are adjacent to each other are known as analogous colors and they provide harmony to a pictures, and a sense of calmness.
It's good to make use of these properties to express the mood you want in your images.
Here's a link to a Hue wheel:
Hi Fabs, read your talk on the color wheel and found it very interesting. I also like the example you chose.
Strong comp that forces my eye to rest on the parrot's eye. All other techs well handled...