Coopers' Hawk (Accipiter cooperii) x Australian Goshawk (Accipiter fasiatus)
This is one of Dave's "experimental" projects. The picture featured on the bird list is the female Australian goshawk. The Australian goshawk is a brown bird, slightly larger than the Coops it is with. The female gos raised 3 Coops taken from the wild, and then one of the males was left in with her. In their second year, there was numerous natural copulations (sometimes two or three times in a 5 min. period) usually in the nest, but no fertile eggs were produced. In their third year together, there was frequent copulation, but eggs laid were broken. It was possible to pull one fertile egg, but it died at pip from an unretracted yolk sack. During that year, the birds were seen building their nest during the entire egg-laying period. At times, both the Australian goshawk and Coops were seen attempting to insert different ends of the same stick into the nest. During their fourth year, there was infrequent copulation during the breeding period. The male did not take much interest in nest-building. All of the eggs were pulled, but none were fertile. During this period, we also had a series of infertile eggs from a proven Harris' hawk pair, and we believed that extreme cold weather had caused the infertility. In the fifth year, the female Australian goshawk killed the Coops.
The Australian goshawk is a calmer bird than the Coops, but is still very "accipiterish". By crossing these two, we had hoped to get a bird that is slightly larger and much calmer than a Coops.
The Australian goshawk was seized in 1985 by the federal government as a smuggled egg. Due to its age, we do not know if this experiment can be repeated. If she lays in this year (2001), we will attempt to inseminate with American goshawk semen.
Having a bird raise its own mate is a very successful way to assure compatability between two birds of like or unlike species. While siblings may have problems breeding naturally, backcrossing a sibling with a parent bird is usually successful. In the case of the female goshawk, the Coops was seen as her offspring, and the Coops saw the goshawk as its parent. In this experiment, we believe that in the fifth year, the differences between the two species may have been too great to overcome.
Pictures:
Click on an image below to view it full size.
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Australian gos (left) as compared to a Coops (right) |
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Close up to the Aussie gos |