Two boys have been arrested after 18 birds were beheaded, a frog speared, fish poisoned and hundreds of windows smashed at a park in south Manchester.
The aviary in Wythenshawe Park was broken into between 1630 BST on Saturday and 1000 BST on Sunday.
It is estimated more than £10,000 of damage was caused in the incident.
A 15-year-old boy was arrested on suspicion of theft and burglary and a 13-year-old was later arrested on suspicion of burglary.
The older boy is also being questioned in connection with the theft of chickens in Rowsley Avenue, Didsbury, on 16 May.
Both are being questioned by officers from Greater Manchester Police.
People with information about the attack have been asked to call police or Crimestoppers anonymously.