La jaula está abierta.

Because Spanish usually uses estar for a state or condition, and open here is a condition the cage is in.

• La jaula está abierta = the cage is open
• estar + adjective/participle often describes how something is right now

Using ser here would sound unusual in normal speech. Ser is more for essential characteristics, identity, origin, and similar ideas.

So for a door, window, box, or cage being open or closed, Spanish normally uses:

• está abierta
• está cerrada

Because abierta has to agree with jaula, and jaula is feminine singular.

Agreement in Spanish means the adjective changes to match the noun:

• masculine singular: abierto
• feminine singular: abierta
• masculine plural: abiertos
• feminine plural: abiertas

So:

• el libro está abierto
• la puerta está abierta
• las ventanas están abiertas

Since jaula is feminine singular, abierta is the correct form.

Yes, jaula is a feminine noun, so it takes la in the singular:

• la jaula
• las jaulas

Many nouns ending in -a are feminine, and jaula follows that common pattern.

A learner might wonder whether there is some exception like el agua, but jaula is not one of those special cases. It is simply feminine: la jaula.

It is the past participle of abrir, but in this sentence it is functioning like an adjective.

• verb: abrir = to open
• past participle: abierto / abierta

In La jaula está abierta, the participle describes the cage’s condition, so in practice it works like an adjective.

This is very common in Spanish:

• La puerta está cerrada
• La tienda está abierta
• La ventana está rota

So even though abierta comes from a verb, here it describes a state.

Usually, no—not if you mean The cage is open.

For a physical thing being in an open state, Spanish normally says:

• La jaula está abierta

If you say es abierta, it would sound odd in most situations, or it could suggest a more permanent quality in some abstract sense. That is not how people normally talk about a cage, door, or window being open.

So the natural choice is está abierta.

Yes, in a normal sentence you need la.

Spanish usually uses an article with a singular countable noun when it is the subject:

• La jaula está abierta
• La puerta está cerrada
• El libro está aquí

Leaving out the article would sound incomplete in standard Spanish.

English often omits articles in places where Spanish does not, so this is a common thing for English speakers to notice.

Yes. The most neutral order is:

• La jaula está abierta

But Spanish can also say:

• Está abierta la jaula

This can sound more literary, emphatic, or context-driven, depending on the situation. For example, it may answer a question like What’s open?

Still, for learners, La jaula está abierta is the best basic pattern.

Not directly. It mainly tells you the current state of the cage: it is open.

So:

• La jaula está abierta = the cage is open

It does not clearly focus on the action or who did it.

If you want to emphasize the action, Spanish might use something like:

• Abrieron la jaula = they opened the cage
• Han abierto la jaula = they have opened the cage
• La jaula fue abierta = the cage was opened

That last one is grammatical, but everyday Spanish often prefers more active phrasing.

Because Spanish adjectives do not just add -a to the English word. You must learn the Spanish adjective itself.

Here the form comes from the verb abrir, whose participle is irregular:

• abrir → abierto / abierta

So the feminine form is abierta, not opena.

This is just part of learning Spanish vocabulary and patterns. A few similar examples are:

• escribir → escrito
• romper → roto
• volver → vuelto

A common Latin American pronunciation is roughly:

• jaula ≈ HOW-lah, but with a Spanish j
• abierta ≈ ah-BYER-tah

A few useful notes:

• The j in jaula is a strong breathy sound, like an English h but usually stronger.
• au is a diphthong, pronounced together, similar to the ow sound in cow.
• In abierta, ie is also pronounced together as one syllable group.

A rough syllable breakdown is:

• jau-la
• a-bier-ta

It is already a complete sentence.

In Spanish, the noun itself is the subject:

• La jaula = the cage

So there is no need for a separate subject pronoun. Spanish does not use pronouns the same way English does.

This sentence has everything it needs:

• La jaula = subject
• está = verb
• abierta = complement describing the subject

So La jaula está abierta is fully complete and natural.