Хотя в небе была одна ворона, дочка всё равно смотрела только на чайку у воды.

Because в meaning in is followed by the prepositional case when it shows location.

• небо = sky
• в небе = in the sky

So this is a normal location phrase:

• в доме = in the house
• в машине = in the car
• в небе = in the sky

If motion into something were meant, Russian would usually use the accusative instead:

• в небо = into the sky

Была is the past tense of быть (to be) in the feminine singular form.

It agrees with ворона, which is a feminine singular noun.

• ворона = crow
• ворона была = the crow was

Russian past tense agrees in gender and number:

• был = masculine
• была = feminine
• было = neuter
• были = plural

So была is used because the thing being talked about is одна ворона.

Because одна ворона is the subject of the clause.

In в небе была одна ворона, the structure is basically:

• there was one crow in the sky

The noun naming what existed is in the nominative case:

• одна ворона = one crow

You would use одну ворону if it were a direct object:

• Я вижу одну ворону. = I see one crow.

So here:

• одна ворона = subject / thing that was there
• одну ворону = object / thing someone sees, etc.

It literally means one, but in context it often carries the sense of a single or just one.

So в небе была одна ворона can feel like:

• there was one crow in the sky
• there was just one crow in the sky

Russian often uses один / одна / одно for this kind of emphasis.

If the speaker wanted to make only more explicit, they could say:

• В небе была только одна ворона.

But одна by itself already suggests singleness pretty naturally.

Both mean daughter, but they are different in tone.

• дочь = the neutral/basic word
• дочка = a more affectionate, familiar, or everyday form

So дочка sounds warmer and more natural in many narrative contexts, especially when talking about a child.

It is similar to the difference between:

• mother vs mommy / my girl
  Not exactly the same, but the idea is that дочка feels more personal and less formal.

Here всё равно means still, all the same, or anyway.

In this sentence, it shows contrast with the хотя clause:

• Хотя в небе была одна ворона... = Although there was one crow in the sky...
• дочка всё равно смотрела... = the daughter still / all the same was looking...

So the idea is:

• even though there was a crow in the sky, she still looked only at the seagull

This is a very common Russian expression.

Examples:

• Я устал, но всё равно пойду. = I’m tired, but I’ll go anyway.
• Он всё равно не слушал. = He still wasn’t listening.

Смотрела is the imperfective past of смотреть (to look/watch).

The imperfective is used because the sentence describes an ongoing action or a scene:

• she was looking
• she kept looking
• her attention was directed there

If you used посмотрела, that would sound more like a completed, single glance:

• посмотрела = looked (once), took a look

Compare:

• дочка смотрела на чайку = the daughter was looking at the seagull
• дочка посмотрела на чайку = the daughter looked at the seagull / glanced at it

In a descriptive sentence like this, смотрела is the natural choice.

Because the verb смотреть normally takes на + accusative when it means to look at.

So:

• смотреть на кого? что? = to look at whom? what?

That gives:

• на чайку = at the seagull

Examples:

• смотреть на небо = to look at the sky
• смотреть на птицу = to look at the bird
• смотреть на чайку = to look at the seagull

So this is not random case choice; it is required by the verb.

Because it is in the accusative singular.

Чайка is a feminine noun ending in -а, and for many such nouns:

• nominative singular: чайка
• accusative singular: чайку

This is the regular pattern:

• девочка → девочку
• мама → маму
• ворона → ворону
• чайка → чайку

Since смотреть на requires the accusative, the sentence uses на чайку.

Только means only.

Here it limits what she was looking at:

• смотрела только на чайку = was looking only at the seagull

That means her attention was restricted to the seagull, not to the crow or anything else.

Word order helps show what только is focusing on. In this sentence, it is placed right before на чайку, so the meaning is:

• only at the seagull

Compare:

• Она только смотрела на чайку. = She only looked at the seagull.
  (could suggest looking was the only thing she did)
• Она смотрела только на чайку. = She looked only at the seagull.
  (the seagull was the only thing she looked at)

Because у воды means by the water / near the water, while в воде means in the water.

So:

• чайка у воды = a seagull by the water, near the water’s edge
• чайка в воде = a seagull in the water

The preposition у means by, near, next to, and it takes the genitive case:

• вода → воды

Examples:

• у дома = by the house
• у окна = by the window
• у воды = by the water

Because у requires the genitive case.

The base form is:

• вода = water

After у, it becomes:

• у воды = by the water / near the water

This is a regular genitive singular pattern for many feminine nouns ending in -а:

• мама → у мамы
• река → у реки
• вода → у воды

So воды is just the correct case form after у.

Хотя means although / though and introduces a contrast.

Structure:

• Хотя X, Y.
• Although X, Y.

So here:

• Хотя в небе была одна ворона, дочка всё равно смотрела только на чайку у воды.

This means:

• even though there was a crow in the sky, the daughter still looked only at the seagull by the water

It sets up an expectation and then shows that something different happened anyway.

Common pattern:

• Хотя было холодно, мы пошли гулять.
• Although it was cold, we still went for a walk.

Yes, but it is natural Russian word order rather than something strange.

Russian word order is more flexible than English, and it is often used to manage focus and emphasis.

In this sentence:

• Хотя в небе была одна ворона sets the background
• дочка всё равно смотрела только на чайку у воды gives the main point

Within the second clause:

• всё равно highlights the contrast: she still did this
• только на чайку highlights the narrow focus of her attention
• у воды attaches naturally to чайку

So the word order helps guide what the listener notices:

1. there was a crow
2. but despite that
3. she still
4. looked only at the seagull
5. the one by the water

English is usually more rigid, but Russian often arranges words for emphasis like this.