The Shamrock Macaw is a very popular bird with two very popular types of macaws as its parents. The Scarlet Macaw, one of the most highly favored macaws, is described as "beautiful and striking". The Scarlet has been the best known South American parrot for over 100 years. The other parent, the Military Macaw, is also a long time favorite pet macaw with a good temperament, very trainable and highly intelligent.
Hybrid macaws are bred for color. Shamrock Macaws are a first generation hybrid macaw, meaning its parents are two species of naturally occurring macaws. Because they are a mixture of more than one type of macaw, the offspring are influenced by the traits and characteristics of both of its parents. Father's have the dominant gene, so this will generally influence the offspring's coloration and overall appearance. The Shamrock inherits its striking coloration from these two attractive parents, the Scarlet influence providing lots of contrasting reds to the greener tones of the Military (animal world.com)