Is "nothing but birds and a few insects" singular or plural?

Is nothing singular or plural?

All by itself, nothing is clearer than the fact that nothing is singular.

However, the original question did not use nothing “all by itself”, and that is where things get sticky.

The question asks which of these two versions should be used:

Nothing but birds and a few insects was to be seen.

Nothing but birds and a few insects were to be seen.

This turns out to be a very interesting question indeed. It depends on how you read that. It could be read in either of these ways:

Nothing (apart from birds and a few insects) was to be seen.

Only birds and a few insects were to be seen.

Since native speakers vary in which of those two readings makes more sense to them or sounds better to them, you should choose whichever you feel more comfortable with.

Details, Details, Details

After reading through grammars and examining various corpora for actual examples of how things like nothing but <NOUN-PHRASE> wind up being used in subject position and what sort of concord they admit or allow, I have come to the conclusion that different native speakers make different choices for this particular situation.

Specifically, both of these types of examples can be readily found:

<NEGATIVE-PRONOUN> but <PLURAL-NOUN-PHRASE> <VERB-SINGULAR>
<NEGATIVE-PRONOUN> but <PLURAL-NOUN-PHRASE> <VERB-PLURAL>

Because both versions can be generated by native speakers, it is hard to say that one is “right” and another “wrong”. In fact, what sounds perfectly fine to one speaker may sound completely off to another.

Below I show why and how this is.

Are negative indefinite pronouns singular or plural?

Short answer: yes. Or either. Or both. Or well really, it just depends.

Long answer follows.

The word nothing is a negative indefinite pronoun. The full list of these is

none
no one
nobody
nothing
neither

Negative pronouns in English can vary in countability and number depending on how they are used. For example, none can be used both as non-count or count.

This is clearest when there is a postmodifying prepositional phrase to signal whether we’re dealing with a count noun or a mass noun.

None of the butter is left.
None of my friends are coming.

This is similar to how premodifying prepositional phrases can work:

A lot of the butter is left.
A lot of my friends are coming.

The logical head of the noun phrase in these is not the same as its grammatical head, in that these pre- and post-modifiers act like determiners or adjectives, which means that they do not affect subject–verb agreement.

One way to look at it is that none of the and a lot of the do not count for agreement purposes. For some people, it turns out that nothing but has the same property. But for others, it does not.

This is easy to see if we replace none of the with the negative determiner no:

No butter is left.
No friends are coming.

We can do the same illustration with a lot of, but now we need to choose much for non-count and many for count versions:

Much butter is left.
Many friends are coming.

The predeterminer all (of) works the same way:

All of the butter is left.
All the butter is left.
All of my friends are coming.
All my friends are coming.

In all these cases, clearly it is butter and friends which are the logical heads of their respective noun phrases, and when that noun phrase acts as the subject of a finite clause, it is the logical head of that noun phrase that controls numeric agreement with the verb.

When the noun phrase has a but in it, it can be used as a conjunction or as a preposition. As a coordinating conjunction, it is the second of a not (only/just) . . . but (also/rather) pair.

Not only Jim's mother but also Jim himself are attending.
Not only Jim's mother but he himself are attending.

Sometimes this acts disjunctively and so can result in a singular verb:

Not Jim's mother but rather Jim himself is attending.
Not Jim's mother but he himself is attending.
Not my mother but rather I myself am attending.
Not my mother but I myself am attending.
It is not not my mother but I myself who am attending.

At other times, it acts conjunctively and so requires a plural verb:

Not only Jim's mother but also Jim himself are attending.
Not only Jim's mother but also he himself are attending.
Not only my mother but also I myself are both attending.

Notice how any personal pronouns involved stay in subject case when they are part of the subject. It would be ungrammatical to put them in oblique case when they act as the subject:

Not Jim's mother but *him is attending.
Not my mother but *me am attending.
Not only Jim's mother but also *him are attending.
Not only my mother but also *me are both attending.

Nothing but birds

Now let’s look at the original problem to be solved:

Nothing but birds and a few insects was/were to be seen.

Here but is acting not as a conjunction but as a preposition meaning except (for). This is not a compound subject at all; instead it is a noun phrase with a postmodifying prepositional phrase. That means it works like none of the and so can be either singular or plural.

None of the birds were visible.
None of the water was visible.

That seems to lead to the conclusion that the original sentence's verb should be in the plural, since its logical head is plural:

Nothing but birds and a few insects were to be seen.

Simple enough answer, but is it the right one?

No. It is not the right answer; it is a right answer. Others exist, as shall be demonstrated below.

Corpus Examples

However, that is not the conclusion universally reached by native speakers. Some make the other choice for the same situation. And there seem to be situations were it really cannot be plural.

For example, here you cannot seem to get away with using a plural verb:

Nothing but my own thoughts was real to me.

Perhaps that is why actual citations in the Corpus of Contemporary American English (COCA) and Google Books show a variety of choices here for the model of:

<NEGATIVE-PRONOUN> but <PLURAL-NOUN-PHRASE> <VERB-SG/PL>

One COCA example uses a singular verb here:

Maybe Pearl was Hiroshima. Nothing but debating points is to be gained by arguing such things. (PBS Newshour, 1991)

But other COCA examples use a plural verb instead:

. . . it was almost impossible for Darryl to distinguish the members of the surgical team; nothing but their eyes were visible. (Analog Magazine, 2012)
. . . so intently was she focused that she screened out a conversation that ended abruptly when nothing but the crusts were left on her plate. (African-American Review, 2005)
. . . my friends, your expense! You do the work of the world yet nothing but crumbs come your way!" (Southwest Review, 1996)

Google Books also has examples using singular verbs in this situation:

By this irruption, however, nothing but the suburbs was yet gained: the entrance into the town was still more difficult. . . .
Tradition, as already mentioned, placed Seming, a son of Odin, on the throne of that country, and from him descended a race of pontiff-kings of whom nothing but their names is recorded.
At best, nothing but their names is known; for who among the multitude of men, who hear or who utter their names really knows anything about their lives or their deeds, or attaches to those names any definite idea?

And it isn’t just for nothing, either; no one can do the same thing. If anything, no one is more resistant to being cast into the plural than nothing is. But not perfectly so.

Here is a COCA example using a singular verb even though the you part would take a plural one:

No one but you has to notice, in order for it to screw up your world. (Mandala, 2006)

That contrasts with another COCA example where the writer has gone exactly the other way and chosen a plural verb after no one but you:

She said no one but you were fit to direct her.

This proves that native speakers make different choices for these situations!

But it gets stranger still. It’s not just the verb number that varies: even the pronoun case does. COCA has curious examples of no one but where the pronoun is in subject case not oblique case.

. . . to us; it required all the subtle tact of which I am capable. No one but I could have done it. No one but I would have done (Lion in Valley, 2008)
. . . In a low, weary voice that no one but I could hear, he muttered: " Enjoy it, kid (American Heritage, 2000)
. . . hand into his jeans pocket, something he did reflexively when he was nervous. No one but she knew that he was probably fingering the silver worry beads she'd (Pink Jinx, 2006)

That’s strange, because just between you and me, one would think it should be oblique case.

And indeed, often it is:

. . . discussing themselves and their world in such a way that no one but them could have known. (Fantasy & Science Fiction, 1998)
. . . Silence in the vehicle surrounded him. No one but him was laughing. He could feel the vehicle slowing down. (Forbidden, 2005)
. . . rude gesture and half ran to lose himself in the crowd. No one but me was watching. (In Shadow Oak, 1991)

Google Books:

The fact remains that she's gone and no one but me remembers her.
striving for some transmutation no one but them understands.
Mr. Paling: Is it not a fact that by the terms of reference Europeans should be in a privileged position, and that now, owing to the right hon. gentleman's interpretation, no one but Europeans has any right to land at all ?
You're in New York City. In a part of Central Park that no one but us knows exists. . . .
Absorption of more work leads to the demand for even more, because no one but us really knows what librarians do, why it is important, and how much of it we can accomplish.
Luckily we only had to shorten our trip by a day, but we did miss the first two days of classes . . . which no one, but us, was concerned about.

Yet other examples show it with a plural verb:

No one but Europeans were allowed to live on the island.
No one but Americans visit this famous spot; so say Englishmen.
The Secret Service had closed off the estate, and no one but police were allowed in, and no one except police — including the party guests — were allowed to leave.

In Conclusion

I have shown that both possible answers to the sort of puzzle posed by the original question do occur in actual text by native speakers.

After reading hundreds of examples, my general sense is that there are more situations where plural concord gets applied here than where singular does.

Additionally, many of the examples with singular concord occur in older or more formal texts. But some are not. It really just depends.

Beyond just conflicting subject–verb agreement, real-world examples demonstrate that not all native speakers agree about the case of the object of the preposition but when used in subject position.

This surprised me.

My tentative hypothesis is that they are construing but to be acting as a conjunction there instead of as a preposition. That would justify leaving the pronoun in subject case instead of switching to oblique case.

Then again, it might also be simple hypercorrection. Hard to say for sure.

Subjects cannot be contained within prepositional phrases. "but birds and a few insects" is a prepositional phrase. "Nothing" is the subject. "was" is the proper verb. There is no argument here.