My interests

[Corey]

Hello,

As an introduction as to why I have joined this group,I have an abiding interest in parrots. Parrots share with few other types of birds four types of opsins in their retinal photoreceptor cells. They have opsins with absorbance maxima in the red, green, and blue, sharing this with us. However, the fourth opsin has an absorption maximum at about 370 nm. Thus, the world seen through parrot vision is far richer in colors detected than is the world we see. Most interestingly, UV reflectance studies have shown that males and females that are to our eyes look identical, actually have different patterns of UV reflectance, suggesting that to parrot eyes, males and females appear different. However, no images have been made that give any idea of what the differences are or give any idea of what the parrots see. Indeed, there is evidence that UV reflectance influences mate choice in parrots. I would like to emphasize that I am interested in reflectance images, not fluorescent images, as some parrots indeed have feathers that fluoresce in the human visible range when illuminated by UV.

Thus, I am looking for someone who has the necessary equipment to take digital images of male and female parrots for a number of sexual monomorphic species. I would like to compare the images and make composite images that show the difference in appearance of the sexes as seen by the birds themselves. I live in the San Francisco Bay Area, but I am willing to travel to participate in these experiments. I have access to live birds and to museum specimens here, as needed. Please contact me if you are interested in a collaboration and possible publication about this topic.

Regards,

Corey Raffel

[Jonny]

I was quite interested in this myself, I heard about it visiting a local zoo, unfortunately they only have males and being based in the UK I doubt I could help you with your research but I'd love to see the results

[colinbm]

Fascinating research Corey & good luck with your studies.

Col

[nfoto]

Welcome to our community. Your topic sounds interesting even to a trained botanist ... hopefully, some of our US members can help you with practicalities.

[Alex H]

Hi Corey,

 

Although I reside in Sweden, I might be able to help. I'll send you some more information in private message.

 

Alex

[renaud]

If there's no requirement for this to be confidential, please keep the conversation open. I, for one, would be interested. The UV reflectance of birds is what got me interested in UV photography first. Because of the technical difficulties I have given up and now photograph flowers and insects, but I sure would love to give it another try if some solutions emerge.

[colinbm]

'Structural Colour', must play a part in this too ?

Col

[OlDoinyo]

Because of the technical difficulties I have given up and now photograph flowers and insects, but I sure would love to give it another try if some solutions emerge.

 

I would be curious to know what 'technical difficulties' defeated you, in particular. Was it the difficulty of framing/focusing upon a subject through an opaque filter? Was it lack of access to a telephoto optic with sufficient bandpass?

[renaud]

Well, it was mostly the impossibility (not to mention the danger) of lighting a distant (5-10m) subject with enough UV-light to freeze the motion (even perched, birds tend to move a lot). Focusing is another problem, but it can be overcome with live view cameras. I bought one of the mirror-only telephotos of the katoptar design for this purpose, my limited testing shows that it transmits some UV, although I never measured the actual transmission or bandpass.

[Alex H]

photograph ... insects

 

birds tend to move a lot

 

I think you are underestimating the capabilities of your equipment. If you can freeze the motion of moving insects on the flower, you should be able to do the same with moving birds. Unless you use UV-flash for insect photography.

[renaud]

Unless you use UV-flash for insect photography.

 

Precisely, that's what I'm doing. It works at close range, but birds are another matter (and a UV flash that powerful would certainly be a hazard to the bird and possibly the whole neighborhood…). Anyway, if solutions come up (e.g. clean ISOs high enough to reach 1/500 at f/8 with sunlight UV alone) I will give it another try.

[rfcurry]

renaud,

There has been considerable work already done on structural UV color in birds. e.g., http://www.aoucospubs.org/doi/pdf/10.1642/0004-8038%282003%29120%5B0163%3ACSOULB%5D2.0.CO%3B2

 

What is also interesting, IMO, is honesty markings and subspecies markings. As you pursue your photos, you will probably encounter some male parrots which have bright UV markings, while others of the same species and gender do not. Are these the honesty markings of a young bird, or indications of a subspecies? That should be a difficult knot to untangle.

 

You might wish to allow yourself some wiggle room on your requirements. Some modern cameras can produce decent images at ISO 1600. Add a lens that is adequately sharp when wide-open -- the Steinheil Cassar S 2.8/50 is one -- and you might be able to get 1/100s. Do you really require f/8? What focal length do you need? Piesker made some fast (relatively) long triplets and a doublet.

[renaud]

Thanks for the link and advice. My problem is that all this documentary work was mostly done with feathers or stuffed animals (possibly sometimes captive birds). My initial ambition was to do it with common and tame but nevertheless wild birds, such as robins, blackbirds, tits and the like. This implies fast shutter speeds and long focal lengths (hence the f/8 requirement, since I haven't heard of and certainly couldn't afford a 500mm f/4 UV lens…). My aim is not documentary either (although that's a side benefit), I'm interested in discovering how different the world looks in UV light (and attempting to make good pictures in the process).