The first two verses in the poem are crucial to set the scene. It depicts the animals as almost dead. It lays the stage for the jaguar to be a complete contrast to the rest of the zoo. To show the laziness Hughes uses imagery particularly well.
The parrots are the main subjects in the 1st verse. He describes them as shrieking and begging humans. 'The parrots shriek as if they were on fire, or strut like cheap tarts to attract the stroller with the nut.' This shows the noise they make and the way they act up to humans so they can get food, which is not natural. The comparison with parrots and prostitutes seems off the wall at first but its very good. When you think about it deeper it works. 'Fatigued with indolence, tiger and lion Lie still as the sun.' This is an oxymoron, this really means tired of doing nothing.
Hughes uses enjambment to capture the mood of the tiger and lion. He goes onto describe 'the boa-constrictors coil Is a fossil'. This is good imagery it depicts the shape of the boa constrictor but also has connotations that the snake is 'frozen in time' perhaps. The finishing line in the second verse is 'it might be painted on a nursery wall.' This is brilliant it gives you the idea that the scene is still as a