Abstract
If you are intending to breed birds of a species wherein the male and female look alike the first major step is to get a true pair, i.e., a male and a female. There are a few hints that might help you pick out a true pair.
First, you must be sure that the birds are mature. Then get a good book that shows the topography of your type of bird (not necessarily the same species but don't use a pheasant topography for a parrot). Make a list of all of the named feathers and parts of the bird's body. Duplicate the list.
Next, catch one of the birds and examine it closely. On your list mark the color of each type of feather. Don't forget the underside of the wings and tail. Mark the dtails of the eyes, the shape of the head and beak. Measure the various parts of the bird and then the entire bird. Record these measurements. When you have put on paper everything your fine-tooth-comb inspection has revealed put a colored band on the bird's leg.
Now catch the other bird and go through the same procedure. Ring this bird with another color. You will wind up with two highly detailed descriptions. Compare the lists. If you have male and female birds the lists will probably show some differences, no matter how minute, in coloring and size.
When the birds have been examined, described on paper, and ringed, put them in the aviary. Observe them closely. This is most important although time-consuming. Often you will note a difference in behavior and voice. Note which bird is more aggressive, which appears to display, which does the feeding, which mounts the other (although sometimes in the frenzy of breeding a hen will mount the male briefly). Observe which bird builds or prepares the nest, and finally, which one lays the eggs. If your birds go through these activities and produce fertile eggs, you can positively identify the male and the female.
If you do all of these things but your birds don't lay eggs or their eggs are infertile you can always take them to a veterinary surgeon who can perform a painless operation for sex determination. In short, by one method or another, there are no birds on earth that cannot be sexed.