A flock of homing pigeons has taken up residence on our roof. How do we know they’re homing pigeons? They’re all banded, they’re very sleek and well-fed, and they seem a bit lost.

They stand on our skylights and look down at us with beaky expectation, as if we know what to do better than they. I think what they’d like to do is move on, but they’re not quite sure to where.

It’s migration season all over the world, creatures on the move. And whether out of habit, necessity or instinct, migration is always a dicey venture.

Billions of birds migrate every year, and every year it gets a little harder for them. Ornithologists at the Max-Planck Institute estimate that up to 10 billion migratory song birds don’t make it from their point of departure to their destination, and statistics are pointing to a 50 percent overall loss of the world’s songbird population in just the past 40 years.

What’s happening?

There are the old culprits of hunting, with some cultures clinging to archaic trapping methods of capturing tiny birds that make barely a mouthful.

I think of these habits, which are worldwide and involve different birds in each region, and when they must have begun.

Was it out of a sense of longing, that the eating something so delicate and that sang so sweetly would somehow impart some of that fleeting beauty to clumsy, earthbound humans? Was it out of basic hunger and the seasonal availability? Was it out of a sense of plenty, just so many of damn things that putting a few dozen in a pie would make no difference?

These days, it seems like people do it just because they can. And old habits die hard.

But beyond hunting, there are the bugaboos of climate change and, probably most relevant, habitat loss. Not just the habitats where the birds overwinter or breed, but the flyover areas. The navigational abilities of the migrating flocks are considerable, but can’t necessarily account for all the new human settlements in areas that used to be resting zones, or dark areas now illuminated by city lights, or absent wetlands, or all those windows that look like sky.

The good news is that there are a number of technological innovations and legislative solutions underway to try and stop some of the songbirds from ending up against a window instead of their summer home, or being confused by light smog.

What will our visiting pigeons do to find their way home? I wish I knew where they needed to go – they certainly keep looking in at me as if I do.

Hopefully, they’ll just be circling, as they do right now, and the right flight path will suddenly occur to them.