nakigoe sae kike reba, zukan de siraberareru.

Here, さえ means something like even, just, or as long as even that much.

In this sentence, 鳴き声さえ聞ければ has the nuance of:

• if I can hear even the cry
• if I can hear just the cry
• as long as I can hear the cry

So さえ emphasizes that the minimum information needed is the animal’s call. You do not need to see it; hearing the cry alone is enough.

A very common pattern is:

• N さえ ... ば = if only / as long as even N

For example:

• 名前さえ分かれば、探せます。
  If I at least know the name, I can look it up.

聞ければ is the conditional form of the potential verb 聞ける, which comes from 聞く.

So:

• 聞く = to hear / to listen
• 聞ける = can hear / be able to hear
• 聞ければ = if one can hear

That means the sentence is not just saying if you hear it, but more specifically if you are able to catch/hear it.

Compare:

• 聞けば = if you hear / if you listen
• 聞ければ = if you can hear

The second one fits better here because the point is whether the cry is available to you as information.

It is built like this:

• 聞く → dictionary form
• 聞ける → potential form (can hear)
• 聞ければ → conditional form of the potential (if [someone] can hear)

So the chain is:

聞く → 聞ける → 聞ければ

This is a very common pattern:

• 読める → 読めれば = if one can read
• 行ける → 行ければ = if one can go
• 見られる → 見られれば = if one can see

That is a very natural question, because English often uses hear for both ideas.

The difference is roughly:

• 聞く = to hear / listen intentionally, or to catch as information
• 聞こえる = to be audible / to be heard naturally

In this sentence, 聞ければ suggests if you can catch the cry well enough to use it for identification.

If you used 聞こえれば, the nuance would be more like:

• if the cry is audible
• if it can be heard

That is not impossible, but 聞ければ sounds more natural when talking about getting usable information from the sound.

れば makes a conditional: if ...

So:

• 聞ければ = if [you] can hear
• 鳴き声さえ聞ければ、図鑑で調べられる。
  = If you can hear even just the cry, you can look it up in a field guide.

When さえ and ば appear together, the whole phrase often means:

• if only ...
• as long as ...
• provided that even this minimum condition is met

So the sentence has the feel of:

As long as you can at least hear the call, you can identify/look it up with a field guide.

Because さえ often attaches directly to the noun, and the expected particle is left out.

So instead of saying:

• 鳴き声を聞ければ

the sentence says:

• 鳴き声さえ聞ければ

This is very natural. The object relationship is still understood: 鳴き声 is what is being heard.

With focus particles like さえ, だけ, しか, and まで, Japanese often omits the ordinary particle when it is obvious.

So 鳴き声さえ聞ければ means:

• if you can hear even just the cry

Here で is best understood as marking the means/tool used.

So:

• 図鑑で調べる = to look something up using a field guide / illustrated reference book

In English, we often translate this as look it up in a field guide, but grammatically Japanese is closer to by means of a field guide.

So で does not have to mean only a physical location. It can also mark:

• a tool
• a method
• a means

For example:

• スマホで調べる = look it up with a smartphone
• 辞書で調べる = look it up in/with a dictionary

Here it is potential, not passive.

• 調べる = to investigate / look up
• 調べられる = can investigate / can look up

So in this sentence:

• 図鑑で調べられる = can be looked up in a field guide / you can look it up in a field guide

Technically, 調べられる can also be a passive form in other contexts, but here the meaning is clearly potential because that is what fits the sentence.

Also, in casual speech, some people say 調べれる, but 調べられる is the standard form.

The subject is omitted, which is extremely common in Japanese.

Depending on context, it could mean:

• you can look it up
• we can look it up
• one can look it up
• it can be looked up

Japanese often leaves out subjects and objects when they are obvious from context. So this sentence is naturally general and practical, like a tip or piece of advice.

A smooth English interpretation is:

• If you can hear even just the cry, you can look it up in a field guide.

But Japanese does not need to explicitly say you.

It has a minimum-condition nuance.

The speaker is saying that hearing the cry is enough for identification. In other words:

• seeing the animal is not necessary
• the cry alone gives enough information
• the condition is surprisingly small

That nuance comes mainly from さえ.

So the sentence is not just a neutral conditional. It carries the feeling:

• Even that alone is enough
• That’s all you need

This is why さえ is so important here. Without it, the sentence would sound more plain and less emphatic.