Growing daylight offers spotting opportunities
- John Lorson: The Rail Trail Naturalist
- January 11, 2022
- 778
This snowy owl, perched on a Wayne County fence post, is not a typical sight, but when populations rise in their native far northern territories, wintering birds will sometimes make their way into our area to the delight of local birders. The bird makes no effort to remain inconspicuous, as in the north it has few natural enemies and is camouflaged from its own prey by blending naturally with the frozen tundra.
Finally, for the first time in several long weeks, I was able to experience a tiny sliver of daylight both on my ride to work in the morning and on my way home at day’s end. The transition from fall to winter is always a tough one on me, and it’s not just because of the cold. After all, one can dress for darn near anything. My biggest issue at this time of year is sunlight — more specifically a lack thereof.
Aside from the general sense of cheer and well-being that a sunny day can bring, exposure to sunlight actually brings a physiological boost as well by way of vitamin D. The UVB rays in sunlight actually power a conversion of dehydrocholesterol in the skin to vitamin D3, a chemical compound essential for the uptake of calcium within the body. Granted, the small amount of sunlight making its way to my face — the only bit of me that’s exposed at this time of year — may be capable of powering little more than a boost in spirit. It is often enough to string me along to the sunny days of springtime.
In summertime when the sun is high in the sky, just 10-15 minutes of direct exposure can produce enough D3 to meet all of the body’s requirements. Overexposure can lead to a host of other problems, of course, but that’s a conversation for another season.
Aside from good health, a bit of daylight goes an awfully long way in the art of catching things with the camera. I’ve seen some pretty spectacular things in the dead of night, but capturing an image and sharing it with the world is often a long shot that never truly materializes. I’ve got plenty of dark, blurry photographs to prove that. Throw in a little glow at the beginning or end of the day, and things change dramatically in the lens.
That same trace of daylight is the trigger for activity in our crepuscular neighbors — animals that move about in the twilight hours. And it provides a brief window to photograph one of my favorite nocturnal animals as well, the owl, if only by merit of the fact you can spot him as he begins the night’s hunt.
One owl species is just as likely to be spotted in the broad light day as in the half-light of dawn or dusk. The snowy owl, whose native habitat is the treeless tundra of the far north, can be found perched in the wide open of field at any time of day. And while not a regular migrant to our area, they seem to appear more frequently as the world warms.
The snowy owl’s appearance in our area is a great reminder of the inter-relatedness of predator and prey. The northern visitors generally appear here not because of famine in their home range, but rather because conditions back home during the breeding season were exceptional.
A nesting snowy owl depends almost entirely on the presence of the Arctic lemming to nourish its growing young. In years when conditions are prime for lemming reproduction and their broods are large and successful, the snowy owl’s young are well fed and considerably more likely to survive to adulthood. An abundance of owls in the north drives the bird to expand its winter range further south, and we suddenly see snowy owls in the bare fields of winter Ohio.
That same increased rate of predator survival (the owl) eventually creates increased demand for prey (the lemming), driving its population back down. The owl population decreases accordingly, and the cycle begins all over again — thus the constant and ever-changing balance of natural populations.
Remember, if you have comments on this column or questions about the natural world, write The Rail Trail Naturalist, P.O. Box 170, Fredericksburg, OH 44627, or email jlorson@alonovus.com. You also can follow along on Instagram @railtrailnaturalist.