Three species of harrier are found in Australia, those being the Swamp Harrier, Papuan Harrier and the Spotted Harrier.
The Spotted Harrier (also known as the Smoke Hawk) is in some respects a unique harrier and highlights the way species adapt to their environment by changing basic instincts so as to survive in a demanding environment.
At first glance nothing seems out of the ordinary with this harrier; it soars low over grasses, crops and other reed-like vegetation like a harrier, has an owlish facial disk like a harrier, and preys on small birds like a harrier. However, unlike all other species of harrier, the Spotted Harrier nests in trees, not on the ground.
This adaptation is likely due to the lack of protection from predation that most harrier species can expect from their nest location, which is usually located in wetlands. The Spotted Harrier is mainly a bird of more arid environments, where it is difficult to find a nesting location that is safe from dingos, foxes, quolls, goannas and other animals likely to prey on eggs and fledglings.
So the Spotted Harrier adapted – it decided to nest in trees to increase the chances of survival of the species. But it has not lost all its basic harrier nesting instincts! The Spotted Harrier will often nest in trees that have thick vegetation or have been accosted by “parasites” such as mistletoe and similar shrub-like plants. The nest is also made with grasses and other matted materials so that the end result is a nest which looks similar to what other species of harrier might construct on the ground.
And from my experience, it seems like the Spotted Harrier is doing very well indeed. In the Killarney area there are several birds that seem to be competing very well in their niche, co-existing with other birds of prey that hunt small birds such as Australian Hobby, Collared Sparrowhawk, Brown Falcon and Brown Goshawk. It is always a pleasure to watch them haunt the fields with their greyish wings, chestnut facial disc and creamy-spotted flanks, contrasting sharply with the bright yellow legs with their long taloned claws!