The Birds resembles all the early plays of Aristophanes in key aspects of its dramatic structure. Such resemblances are evidence of a genre of ancient drama known as Old Comedy. Variations from these 'conventions' are significant since they demonstrate either a trend away from Old Comedy, a corruption in the text or a unique dramatic effect that the author intended. Variations in this play are found in the following conventions:
- Agon: The agon is a debate or formal argument constructed as a 'symmetrical scene', with two declaimed sections and two songs. The protagonist generally defeats the antagonist in the debate and this decides the outcome of the play long before the play actually ends. The agon in The Birds (lines 451–626) is conventional in form but there is no antagonist – the two main speakers are Pisthetaerus and his friend Euelpides, with Pisthetaerus delivering a speech and Euelpides providing supportive comments. The birds provide a willing audience and they are easily won over to the protagonist's point of view. A similarly one-sided agon is found in the next surviving play, Lysistrata.
- Parabasis: The parabasis is an address to the audience by the Chorus in the absence of any actors. Generally there is a long parabasis in the middle of the play, including a 'parabasis proper' in which the Chorus speaks as the author's representative on issues relating to his career, and usually there is a shorter parabasis near the end. In this play, the first parabasis (678–800) and the second (1058–1117) are conventional in structure but the Chorus always speaks in character as birds. Instead of speaking about the poet in the 'parabasis proper', the birds speak about themselves, outlining their genealogy, their value to the audience and their effect on the audience's vocabulary – in all these topics however there are amusing echoes of things a Chorus would ordinarily say on behalf of the poet. This 'parabasis proper' is in fact almost a satire on the convention of a parabasis proper.
- Unwelcome Visitors: The protagonist's early victory in the agon generally tends to ease dramatic tension early in the play and this is usually offset to some extent by a stream of minor characters or 'unwelcome visitors' that have to be chased off by the triumphant hero. This play is exceptional in that there are three waves of unwelcome visitors – the first wave comes before the walls of Cloudcuckooland have been completed, the second wave comes immediately after and the third wave comes as a delegation from Zeus. This repetition is the reason why The Birds is much longer than the other surviving plays.