In Russian, many nouns ending in -а or -я are feminine. Ворона ends in -а, so it is feminine.
That is why:
A useful comparison:
Because after у, Russian normally uses the genitive case.
The base form is:
But after у:
So окна here is the genitive singular form of окно.
Here у means by, near, or next to.
So:
It does not literally mean at in every context, and it does not mean the crow is necessarily on the window. It just tells you the crow is positioned close to it.
Сидит is the 3rd person singular form of сидеть (to sit).
The subject is ворона = the crow, which is singular, so the verb must also be singular:
Since there is only one crow, Russian uses сидит, not сидят.
It can mean either, depending on context.
Russian present tense often covers both:
So Чёрная ворона сидит у окна could mean:
Usually the situation tells you which one is meant.
Russian has no articles.
So ворона can mean:
And окна can mean:
The exact meaning depends on context. This is very normal in Russian.
Yes. Russian word order is more flexible than English because the endings show the grammatical roles.
The neutral order here is:
But you could also say:
These versions are all grammatical, but the emphasis changes:
Чёрная is pronounced roughly like CHYOR-na-ya.
Important points:
Also, in printed Russian, the dots on ё are sometimes omitted, so you may see Черная. But the correct pronunciation here is still чёрная, not черная with plain е.
Because ворона is the subject of the sentence, so it stays in the nominative case, which is the dictionary form.
But окно comes after the preposition у, and у requires the genitive case:
So the structure is:
Not usually. У окна means by the window, near the window, or next to the window.
If you want to say on the window or on the windowsill, Russian would normally use different wording, for example:
So у окна is about proximity, not being physically on top of it.