Nine birds, including an endangered swift parrot, had their heads smashed in or ripped off and more than 60 animals were missing on Saturday after vandals went on the rampage at an Australian zoo.
Tasmania Zoo owner Dick Warren said he found the mutilated animals when he opened up on Friday morning, finding "door, after door, after door open and all the locks had been cut, with birds missing and birds dead".
"Either they have just caught them and banged their heads or pulled their heads off, it's a pretty sick thing to see," Warren told ABC Television.
"It's heartbreaking to see them. How could people do this sort of thing? It hits you so hard."
Police said "a number of animals escaped their enclosures, with most being recaptured", adding that two chainsaws were also stolen from the zoo complex.
Two rare swift parrots, a yellow-tailed black cockatoo and five quolls -- a carnivorous native cat -- were among the animals still on the loose in what was described as a devastating blow for the zoo's breeding programme.
"We're trying to increase numbers of threatened species and we've lost a good part of that programme," said keeper Courtney McMahon.
The zoo is also part of a national breeding programme for the endangered Tasmanian devil, which is almost extinct in the wild due to a contagious facial tumour, and McMahon said it was a huge relief no devils had been freed.
"The way that the birds were released, if these devils were released like that it would be a death sentence to them," she said.
"There's a good chance that they would, in the wild, contract the facial tumour disease."
