Neil G this is the theory as I was taught for interior design - when using green as the primary colour red is exactly opposite on the colour wheel and is classed as complementary, red/orange is split-complimentry to green as is red/violet, and full orange and full violet are triadic (to be used in threes).
For Red as the primary colour the complimentary is green, split complimentaries are blue/greens and yellow/greens, triadics are blue and yellow.
Andy R's olive hummingbird would be a yellow/green and works with the full red of the hope components as a split complimentary.