Does Flash Harm?

First, I want to say that I have tried very hard not to harm or disturb any birds in the course of my photography. Many of the techniques I describe utilize one or more flashes. It has been very difficult to find any objective information as to how the flashes may harm the birds.  A literature search will not really find anything specific to hummingbirds. But to be on the safe side, I now have moved away from controlling or interfering with birds for the purpose of a photo.

You will hear tour hosts state that this is not an issue. The pro-arguments describe how some birds do not even react to the flash(es), and even the ones that do come right back to the feeders. And I have seen this. Also, in a multiple flash setup, which is very common, a single flash that the bird might experience by direct view would consist of only a fraction of the total light needed to expose the subject. 

In the course of photography, the humane photographer should be aware that birds are commonly stressed in many ways. Who is to say whether a flash is any more or less stressful than invading a bird’s space or otherwise controlling their behavior for the purpose of a photograph.