What does 'themselves' point? Is that 'birds'?

[Boddy]

English Grammar Tests, Elementary Level

ESL/EFL Test #40 "Reflexive Pronouns", question 6

He had watched birds fly by throwing ......... into the air.

(a) yourselves
(b) themselves
(c) ourselves

English Grammar Tests, Elementary Level

ESL/EFL Test #40 "Reflexive Pronouns", answer 6

He had watched birds fly by throwing themselves into the air.

Correct answer: (b) themselves
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what does 'themselves' point ? Is that 'birds'?

Thanks.
Boddy

[Mister Micawber]

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Yes
.
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Native English teacher at Mister Micawber's

[Saneta]

He threw the birds into the air?

[Mister Micawber]

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No, the pronoun is reflexive. Please study that grammar word.
.
_________________
Native English teacher at Mister Micawber's

[Saneta]

''He had watched birds fly by throwing themselves into the air.''Please write this sentence in other, equivalent words for my better understanding.

[Mister Micawber]

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Did you study REFLEXIVE PRONOUNS?
.
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Native English teacher at Mister Micawber's