I posted a photo of a male Cairns Birdwing a couple of weeks ago with the comment that they are so common that “I rarely bother pointing a camera at them.” As usually happens in such cases, I proved myself wrong soon afterwards.
The occasion was my sighting of a female which I thought might be of the Northern species, the New Guinea Birdwing (Ornithoptera priamus), which shouldn’t be seen in Townsville according to the books. I then wanted to check that the local males weren’t (also?) New Guinea Birdwings but that meant getting a good look at the upper surface of the wings, which is not at all easy.
Birdwings and Ulysses on any rack of tourist-trap postcards lie around with their wings gaudily spread but in real life they do nothing of the sort. The wings slam shut as soon as they perch, presenting their much more discreet undersides to the gaze of predatory birds. Almost the only way of getting a photo of the upper sides from a wild swallowtail is to take a burst of shots of a hovering butterfly and throw away most of them. That’s how I got this one.
There are a few points of interest:
- Getting a really sharp, clear photo by this technique is a fluky business. You need lots of light so the shutter speed can stay high enough to freeze the movement (I didn’t have that luxury), and enough shots that at least one of them is well composed.
- It is definitely a Cairns Birdwing, not the northerner, because the large central black area has no green streak through it. That’s a little disappointing but not surprising.
- The wings are catching the light at very different angles and show the same kind of apparent colour-change as the Eggfly. In this case, the bright yellow-green of the wing becomes bluish-purple when seen at an acute angle; it can look even more purple in flight, depending on the angle of the sun.
- And this is an old, battered individual. The trailing edge of the left fore-wing is ragged, and the coloured areas have scratches where scales have been scraped off. This sort of damage is why I noted that the Lurcher (click here and scroll down) was rather elderly.