Does anyone know what kind of bird this is?

It’s medium-to-dark gray and the tips of its wings and and tips of its tail feathers are white.

And when it’s standing on the ground it’s tail is at a 45-degree angle between the ground and the sky


Location? It’s vital to know where the bird was seen.

My point exactly. Northern Mockingbird in an area where they occur.

New York City

The shape looks like a Mockingbird, and so does your description. Very common birds in the mid Atlantic, so I strongly suspect that’s your bird.

Thank you, andy.

Good opportunity to plug the Merlin app, associated with Cornell.
I use it whenever there’s a new visitor in my back yard. It’s pretty good at identifying them.