Other Common Names
Northern Citrus Butterfly , Capaneus Butterfly, Canopus Butterfly

I saw a number of Swallowtails in Cairns, though I have no idea how many of them were of this species as I rarely saw any of them settled. I was fortunate to get photos of this specimen - it landed for a minute on some shrubs at the side of a path. Over the years, on many trips to Cairns, I saw plenty of these butterflies around but they never settled for long enough to allow me to take photos.
However, on my first trip to Darwin in April 2018 I found the NT subspecies (canopus) to be more cooperative as well as more attractive. I frequently saw them land with their wings spread wipe, and once settled they were happy to pose for photos.

Cairns - April 2006
Darwin - April 2018