Monday, November 13, 2023

Eastern Screech-Owl in dark woods


A gray morph (not "phase" as color forms are incorrectly often referred to as) Eastern Screech-Owl stares from its perch in an inky woods. Owl eyes, in comparison to human eyes, are proportionately enormous and in some species - including the next owl species that I'll post about - can make up 5% of the total mass of the owl. Owl eyes also have many more rods per cone, thus their eyes are far more efficient at detecting movement in dark conditions. The net result is eyes that are dozens of times better at harvesting light than human eyes.

Shauna Weyrauch, I and about 25 others had a great evening owling last Saturday night with Blake Mathys, an owl expert and bander in west-central Ohio. We observed or heard three owl species, including the one above, and another species which is quite special, and I'll write more on that one later.

PHOTO NOTE: With highly nocturnal creatures such as owls and bats, it's better NOT to pop a bright flash in their faces. But light is certainly required, as even at the highest ISO setting and widest aperture it won't be possible to harvest adequate light for an exposure in extremely dark conditions. Blake spotted this owl - one of a pair that he knows well - with infrared glasses, and then we used a flashlight beam to illuminate the bird so that all could admire it. My experience with lighting screech-owls in this way is that it seems to bother the low-key birds little, and certainly doesn't have the blinding effect that the brilliant and sudden pop of light from a flash would have.

I have a cool device known as a Neewer CN-160 dimmable light panel. It mounts on the hotshoe of my camera and provides an adjustable and constant light source. I can put just enough light towards the subject to find focus and illuminate it enough for photos. To avoid turning the Neewer up to blinding light levels, I use a higher ISO (much as I dislike having to use high ISO settings, but there is a time and place for them). The settings for this image were ISO 6400, f/8, and 1/200 shutter speed. As we weren't especially close to the owl - maybe 20-25 feet - and I used a 100mm macro lens (on the camera for the primary subject of that evening), I also had to crop a fair bit. So, the graininess associated with a higher ISO is manifesting a bit, but it is still a usable image. And the owl was still there when we departed, no worse for the wear.


Vireo said...

Jim, Like your comment about not using "phase" for Screech Owl color. I go beyond "morph" also as morph indicates change as in "metamorphosis". I prefer and use "form" as in "gray or red form" to indicate color differences.

Jim McCormac said...

I use morph as it's the accepted term, and consistent with most publications such as Cornell's Birds of the World, the Sibley Guide, and most other literature. I agree, it does seem a funny word for it, as morph suggests change and these color forms are stable.

Woody Meristem said...

Very nice photo. I have the same light panel, it's great for situations like yours with the owl and I've used it for fungi as well -- the only thing I don't like about it is the bulk in my pack, but it's often worth carrying.