Есть of existence with prepositions.
I have a technical everyday language Russian grammar question to ask you. As I am seeing through the beginning lessons I am doing and redoing (I have been through the tree three times or more and am capable of reading short news articles in Russian), asserting existence of something in one's possession or existence of something at a location is indicated by У (possessor : genitive) есть (object possessed : nominative) and В, На... (location : prepositional) есть (object located : nominative).
Most of the times I am required to put the есть verb form (there is) after each У clause to indicate presence in one's possession, and also after each В or НА clause to indicate presence at the indicated location. У неё есть дом : she has a house. В доме есть всё : there is everything in the house, or the house has everything, and I am most often in such cases given an error message if I omit the verb of existence. But sometimes, conversely, I am given an error message if I put the есть of existence in small sentences such as В дереве птица : there are birds on the tree, and У меня мыши : I have mice (at my place). How to tell when one must add the есть for the sentence to sound meaningful in Russian and when is it more correct to omit it?
As I understand it (and I'm happy to be corrected):
есть would never be used with body parts or any sort of illness.
есть implies "got one of those" when it's not assumed that you've definitely got one of those.
Your example of birds in a tree - it's totally natural for birds to be in a tree, therefore есть is not required, but you might have put it in IF that was a tree that everyone knows birds don't usually go in and you're pleased to see them.
есть emphasises possession of something, and normally something you want to have.
For example, if you asked whether a boat has a restaurant, you'd use есть, but if everyone knew that the boats there had restaurants and you were asking if that particular boat had a restaurant, you wouldn't use есть but otherwise the sentence could be identical.
I don't think whether it's a в or на clause makes any difference. It's the specifics of possession that matter.
generally mostly true, but:
body parts - can be used in weird situations sometimes, one of the examples that comes to mind would be some sort of an anomaly (у меня есть шестой палец на руке).
illness - can be used for chronic illnesses, although I'd say it sounds better without есть anyways
boat/restaurant example - in all the cases I oculd think of when a minor object is located within a bigger one, есть sounds more natural and shouldn't be omitted, no matter how generally true the question/statement is.
Here are rules I found on one website:
Don't use есть:
1) with abstract nouns # У меня встреча (У меня вечеринка);
2) when a phrase reflects rather a location than possession of something (# У меня в кармане перчатки);
3) when you describe someone's appearance or character (# У него зелёные глаза. У него спокойный голос);
4) when you have a word that describes an object (noun). # У меня есть брат. vs У меня два брата. У меня есть дом. vs У меня большой дом.
I hope it will help you.
The info are taken from this source https://marjulia.livejournal.com/99180.html
That's my language and yet I got no idea what the rule of thumb here is, I would like to know it as well; I can only intuitively tell it for each separate case.
So far some minor notes: В дереве птица means "there is a bird INSIDE the tree", you should use На дереве for "on the tree...". На дереве есть птица would mean there is some sort of a scratched picture of the bird on the tree that is always there. У меня мыши (considering it is a stand-alone sentence and not part of the conversation) means "there are mice at my place" [and they are not welcome there], while У меня есть мыши is more likely to mean "I have mice as pets".
It is important to understand whether there is an accent on the word -есть. It is possible to understand the meaning of a phrase without it.
Do you have money. У тебя ЕСТЬ деньги. Да, у меня ЕСТЬ денги. Here есть is important. Where is money? Где деньги? Деньги - у меня. You don’t need есть here.