Let's say I'm inspecting a room I want to rent and notice a distinctive smell and also a mousetrap. I say "Здесь мыши!" (There are mice here!) and walk away. I can't say "Вот мыши" (Here are mice) in this context.
On the other hand if I'm playing a game where I have to find mice in a picture and I finally find them, I say "Here are the mice!" (Вот мыши!) I can't say "There are mice here".
It is the present form of "to be". We used it as a statement of existence. In the present tense, there is a distinction between using "есть" to express whether something exists, among other things, or there is none of it—and not using есть to express where something is OR to say what exactly there is (the focus is on the identity, not the fact of existence).
It should sound sort of confusing.
English translation does not make any difference here, so we try to allow both options if they both sort of make sense.
In Russian, a question like "Are there any animals here?" could elicit a response "Здесь есть мыши" whereas a question like "What is here?" can be answered with "Здесь мыши".
If you need to specify where an object is, no есть is used:
- Мой велосипед справа. = My bike is on the right.
- Телевизор на кухне. = The TV is in the kitchen
- Наша собака в машине. = Our dog is in the car.