Q: I really enjoy owning and breeding the Pyrrhura conures, but I am concerned about the mutation varieties and how one should go about breeding them. It gets very confusing, with terms like “split to” and “visuals” and the like. Will a visual to a normal produce visuals? Will a split to a normal produce visuals? Does the reasoning behind breeding mutations apply to all exotic birds, and if so, why are there so many mutations of say, ringnecks and cockatiels, and not other types of birds such as conures? Help!

A: Explaining the inheritance possibilities for the different types of mutations could fill a book. There are some simple rules, however, that, if followed, will eliminate most of the confusion. The first thing to remember is that most color mutations can be classified into one of two categories: recessive or sex linked.

The inheritance rules for one are completely different than those for the other. In order to begin thinking about what to do, you must first determine which set of rules the mutation in question falls under. When a new mutation occurs, it must be determined through test breeding which of the two categories it is in. In most cases, this ground-breaking work has already been done with similar-colored birds that have mutated in similar ways.

When trying to determine what rules to follow concerning color mutations in birds that are naturally green, we need to look no further than the work that has been done with ringnecked parakeets (Psittacula). So far, this has proven to be correct. The three most familiar mutations that have shown up in green birds are the blue, yellow (lutino) and cinnamon.

So far, all blue mutations of green birds have proven to follow the recessive rules. These rules say that either parent can pass on their blue genes to any of their offspring but only those that inherit it from both parents will be visually blue. Those that are blue are said to be “visuals.” Those that have inherited the blue trait from only one parent will have normal green plumage but will be able to pass on the gene to some of their offspring. These are called “splits.” When a visual is bred to a normal nonsplit, all the offspring will be normal green in appearance but be carrying the blue gene. When two normal appearing green birds that are both split for the blue gene are bred to each other, there are three possible outcomes: Long-term statistics show that 25 percent of the babies will be blue (visuals), 50 percent of the babies will be colored green but carry the blue gene (splits), and 25 percent will be green without carrying any blue gene (normals).

The only way to identify those green birds that are caring the blue gene from those that are not is to test breed. If you put a visual blue with a green bird that is split to blue, all offspring will be either blue or green split to blue. Two blues will throw 100-percent blue babies.

The yellow color mutation (lutino) so far has proven to always be “sex linked.” That is to say that the sex of the bird will be a determining factor as to whether or not it has the ability to inherit or pass on the gene that causes yellow. When you put a visual male with a normal hen, all females will be visual, and all males will be green split to yellow. If you put a visual female with a normal male, all male offspring will be split to yellow, and all females will be normal green (split to nothing). If you put a split male with a yellow female, the babies will be one of the following four possibilities: green males that are split for yellow (splits), yellow males (visuals), yellow females (visuals) and normal green females (split to nothing). With sex-linked inheritance, there cannot be any females that are split. They are either normal green or yellow. If you breed a split male with a normal hen, you will have split males, normal males, yellow females and normal females. In sex-linked mutations, a split male can produce visual daughters with any female. The only similarity that these rules have with those that govern recessive mutations are that when you put two visuals together you will get 100-percent visual (yellow) offspring.

The third most familiar mutation is the cinnamon. This is really a tan or brown mutation, but in normally green birds it shows up as varying shades of yellow that are masked by varying shades of green. Any areas that are normally black will show up as brown, tan or horn colored. This includes the toenails, beak and the tips of the flight feathers. Their eyes can be brown, ruby, pink, red or normal. Some variations of the cinnamon are given different names like “fallow” or “Isabelle.” To make things even more complicated, the cinnamon mutation can be either sex linked or recessive. Only breeding experiments can determine which is the case.

The reason that there are so many mutations in cockatiels, ringnecks and lovebirds is because of constant inbreeding that knowingly or unknowingly happens when bloodlines are limited. Mutations in all birds are extremely rare in the wild. This is because of the highly varied gene pool that is available under wild conditions. As soon as you decrease genetic diversity, you increase the possibility if mutants popping up. Now that importation of new bloodlines is over, you will, over the years, start to see more mutations in birds like the conures. This will be due to the inevitable inbreeding that will take place.