Apparently there is a wave of restrictions sweeping Costa Rica banning the use of multi flash photography for hummingbirds at a number of locations. There was reportedly a statement by a “professor” from a Costa Rican university purporting to say that it harmed avian eyes and even could result in blindness. As a physician, this seems like nonsense to me. It would be be highly unlikely that a flash duration of 1/10,000 second at 1/16th power (typical settings for multi flash photography) would harm anything. As one who has done this type of photography, I have never noticed any detrimental effects on hummers, who, after a few initial shots, completely ignore the flashes.
I would appreciate everyone’s input here and particularly any references in the literature that might be useful in counteracting this trend. Thanks so much!
i have no evidence to back up my own flash practices, but i would tend not to use direct flash, especially at close distances on vertebrates. fill flash might be better, but i think i still would avoid it if possible. i don’t use flash at all on human babies.
the other thing is that even if there is no potential for permanent blindness, the temporary night blindness that could be caused by a flash might be an issue. when i run at night on city streets, i actually wear sunglasses because the lights from oncoming cars would otherwise leave me temporarily night blind, which is a bad thing when running in the dark.
ditto with strobes. even if they would cause no eye damage, they can be disorienting. i’d prefer not to disorient my subjects if possible, unless it’s for a good reason.
I occasionally use flash in low-light conditions, or when spotlighting. I can only comment based on the reactions I’ve seen in the organisms I photograph, so I’d be interested in hearing actual science behind it.
The argument I’ve heard from several “spotlighters” (tour guides doing owl or noct. mammal tours) is that a short burst of light is not nearly as harmful than a continuous exposure (e.g. a torch/flashlight pointed at the critter). The general consensus I’ve learned is using red light to find something, then (white) flash for photography.
This seems to be fair because you can tell when something is afraid of and directly changes its behaviour from light. For owls, they seem to turn away and fly off if you keep a (white) torch on them, while using red light and several camera flashes doesn’t affect their behaviour. For nocturnal mammals I have noticed a similar case although I have less experience there.
I always thought a sudden burst of light would be worse since it is sudden, with no period for the eyes to adapt. But based on the behaviour I see, sudden bursts of light rarely seem to cause a negative effect unless this is abused. If something is running away from you, you’ve already made enough mistakes, let alone with light. Diurnal birds often flinch at the first burst of light, but after the second or third they no longer react to it.
Well, at laest in some areas, birds are often subject to bright flashes in thunderstorms. So there’s at least a sort of natural analogue and it probably doesn’t hurt them as long as they aren’t hit by lightning. Whereas a bright continuous white light out at night… nothing natural really does that.
When I was in Costa Rica this past January, a lot of guides were pretty anti-flash, especially those leading night hikes. And in some small reserves where there are night hikes every night, I understand that, to a degree. Of course, most of the guides were also still saying that baby vipers are more dangerous than adults, which has been widely debunked.
One of my guides, however, was OK with some flash, pointing out that having 4-8 high-intensity flashlights trained on the organism is likely much worse than a few flashes. I do use diffused flash in my night photography (pretty much all arthropods and herps, not birds) but try to not take too many photos. Although I confess to have at times used it more than I should have.
As to how much the flash affects the organisms, I haven’t been able to tell from my experiences.
Let me step back in here to perhaps clarify the issue as I see it. There are two questions: Is there data to support that the use of flash photography in the natural environment to photograph animals either (1) alters behavior for any significant period of time or (2) has a permanent detrimental effect on any ophthalmological or neurological structure?
I realize this has ballooned out from the topic of multi flash photography for hummingbirds, but I suppose that was inevitable.
I had already read the article by the veterinarian that was referred to, but thanks for doing the search that resulted in it.
I guess one might be able to do a study on chickens or something exposed to various levels and durations of flash and examine their retinas with an ophthalmoscope (does anyone do that?) to look for retinal damage. My guess is that it would take concentrated laser exposure to show damage, as in human treatment of diabetic retinopathy.
It used to be a serious thing in regards to flash photography and archival materials, such as artwork. I think it still is to a degree, but perhaps out of habit.
Technology has come a long way, and flashes are no longer the high intensity bursts of radiation that they used to be. Also, cameras are able to work with lower light levels, so flash lighting doesn’t need to be so intense. I think there would need to be evidence of damage done before one could seriously consider such claims.
I know this has changed from the main topic a bit in that we are sort of trending towards behaviour/interruption rather than physical eye damage, but I think we can judge a bit based on the former – if something really hurts a creature’s eyes, it is not going to sit there and take it. It’s going to run or turn away at the first opportunity.
I think a lot of people take strong stances on “no flash” more because of perceived moral reasons, and because constant regular flash does actually disturb animals (a problem on tours no doubt if they are run in the same place on a daily basis).
“Wildlife Watching and Tourism” by Richard Tapper is a 2006 publication of the United Nations Environment Programme and is described as a “study on the benefits and risks of a fast growing tourism activity and its impacts on species.” (I found a pdf of it by searching Google Scholar.) It uses a series of “Case Studies” to discuss issues. In the section on “Viewing Cranes in Muritz National Park, Germany” flash photography is cited as a disturbance to cranes: “changing their pre-resting habits and flight patterns.” How they arrived at that conclusion is not detailed. An older book, “Wildlife and Recreationists”, edited by Knight and Cole (1995 Island Press–available on Google Books) has a chapter devoted to “Wildlife Responses to Recreationists” but the conclusion is that studies are needed to establish what the long-term effects on wildlife of various activities really are.
My last birding trip to Costa Rica was 8 years ago and the issue of flash photography (in particular for hummingbirds) was already a topic of discussion. I cannot now remember the name of the lodge where the story was told that “the photographers” had caused a certain species to leave and not come back. The science may be missing, but the impression is certainly strong that flash is disturbing to birds. I have chosen not to use flash at all.