は or が in the example "朝起きるとき、鳥 ( ) いつも歌います"?


Following up on my earlier question, I want to check if I've got a feel for
this subordinate clause particle use correct. This is probably a duplicate,
but it really helps me understand things better if I'm posing the question
myself. If this infringes any rules, though, I'll happily remove it.

In the sentence

> 私 ( **が**? **は**?) 朝起きるとき、鳥 ( **が**? **は**?) いつも歌います。

which instance uses が, and which は? I get the feeling the first instance is が,
and the second, は, but I could be wrong.

Any help is much appreciated.




It actually depends on the context, but the "usual" way to say this is:

> 私 **が** 朝起きるとき、鳥 **が** いつも **歌っています** 。  
>  When I wake up, (I find) birds are always singing.

  * が should be used after 私 because 私 is in a subordinate clause (私が朝起きる時 is the subordinate clause.) This is the basic rule. As an exception, in rare contexts where you're comparing 私's mornings with someone else's mornings, は can be used.
  * が should be used after 鳥 because the word 鳥 [has probably not been introduced into "the universe of discourse"](https://japanese.stackexchange.com/q/22/5010). If you have already mentioned these 鳥 before this sentence in some way or another, は should be used. In other words, 鳥は is " _the_ bird(s)", 鳥が is "bird(s)" without "the".
  * I replaced 歌います ("birds (will) sing") with 歌っています (progressive form, "birds are singing"). Saying 歌います sounds like these birds are waiting for 私 to wake up and start singing only after the wake-up.




In your example, "私は" sounds unnatural because it gives too much emphasis on
"私", while actually it's so much unimportant that most of native Japanese
speakers would omit it at all.

You have also to note that the verb "歌う" is only used when talking about human
beings. When talking about birds, you have to use "鳴く" instead.

And as you're talking about a natural phenomena which is still occurring in
present, it's definitely better to use continuous form.

So the correct sentence is:

> 朝起きるときはいつも鳥が鳴いています。

