DEAR JOAN: There is something that I have noticed for years, and I finally decided to ask the only expert I know.

At the southbound Thornton Avenue exit to Interstate 880 in Newark, there are some power lines that extend all the way across the freeway. Every time I go that way I see many birds sitting on the lines, but only on the southbound side, never on the other side.

This is not a once-in-a-while thing; I’ve noticed it for many years.

I’ve never seen them fly away, they all just sit there. Can you think of anything special about these particular power lines?

Inquiring minds want to know.

— Sherry Hughes, Newark

DEAR SHERRY: Not being able to read bird minds, or the minds of any living beings, I can’t say for certain, although I’m sure they have an excellent reason. I can, however, list a few possibilities.

First off, birds really like sitting on elevated lines, whether those are power lines, telecommunication wires or cable lines. The high wires provide an excellent vantage point for surveying the area, giving them a bird’s eywe view of the territory. From there, they can look around for food and watch out for predators.

The lines are also a convenient spot for taking a rest and as there are other birds on the line, a chance to converse. They come and go as they please, but it’s not likely they would all fly off at once unless something really frightened the entire flock. It might look like the birds sit there all day and night, but it’s a revolving cast.

Such gatherings also provide some communal support and protection from predators, and in the winter, the combined flocks can offer a little extra warmth.

Considering how much power is surging through the lines, we have to wonder how the birds can casually perch on them and avoid electrocution. The answer? Science.

Just like water, and nature itself, electricity seeks a balance. It flows from high energy points to low energy points. A bird sitting on the wire doesn’t interrupt or redirect the flow, but if it was to have one foot on the wire (high energy) and another on the ground (low energy), the electricity would seek to balance, redirecting through the bird to complete the circuit, with deadly consequences. The birds are remarkably exact about the positioning on the lines, keeping a small but equal distance between them, and avoiding touching anything else.

Why the birds choose one wire and not the other most likely has to do with environmental factors. The wind might be stronger on that side, the wires might not provide the same vantage point, or there could be something on that side of the freeway or the lines themselves, that the birds just don’t care for.

The birds like a clear pathway when they fly off the wire, and the ones on the northbound side might be more advantageous.

Wish we knew for certain, but maybe one day the birds will talk.

The Animal Life column runs on Mondays. Contact Joan Morris at AskJoanMorris@gmail.com.