"Is it a bird?"
Translation:É um pássaro?
Silly question: In English "She sings like a bird" is a nice thing....is it the same in Portuguese? I don't want to get slapped in the face....I made that mistake in India, I said "Your son is a little monkey" which is cute/nice in English....but in Indian the word for monkey "Bandar" is kinda like calling someone a rat. "Your son is a rat!"...SLAP!
"Isto" means "this", so using this word would imply that the (possible) bird is near the speaker. But "É um pássaro" gives no information about where it might be.
"Is" has two possible translations: "é" and "está". But they have different meanings: roughly speaking (there are exceptions), "é" means a more permanent state of being, whereas "está" refers to a transitory state (something that is happening at the moment it is being said). For example:
"He is funny" = "Ele é engraçado"
"He is late" = "Ele está atrasado"