Det Sgt Stuart Wales says the woman's pet budgie was killed and disposed of by the robbers in front of her.
Burglars have snapped the neck of an elderly woman's budgie in front of her after she refused to hand over money.
South Wales Police said the 78-year-old woman was also threatened with her own walking stick, pushed into a chair and then locked in her house.
The two robbers, who escaped with £150, had broken in while the woman was watching Emmerdale on TV in the lounge of her home in Cathays, Cardiff.
Police said the woman had lost her pet, a "soulmate" in a "brutal" manner.
The burglars demanded £100 but she refused.
She said she had no such money in her house but she was threatened before the men searched her house and stole £150.
'Badly shaken up'
Before leaving the house in Whitchurch Road on Friday evening, one of the men killed her pet budgie by snapping its neck in front of her.
Det Sgt Stuart Wales, of Cathays CID, said: "This was a despicable crime on an elderly lady who is in poor health, where we believe these men have targeted her because of her age and because she lives on her own.
"She has been very brave throughout the whole ordeal but has been badly shaken up.
The robbers escaped with £150 after killing the budgie
"The victim is deeply upset because not only has she been the victim of a crime, she has also lost her pet budgie, her soulmate, in a brutal and disturbing manner."
The burglar who killed the bird was wearing a black beanie hat, a dark scarf across his face, a dark tracksuit and dark woollen gloves with a white square-type pattern on them. He spoke with a local accent.
He was possibly in his 20s and was thin with a pale complexion.
The other man was about the same age but shorter, and had a distinctive walk. He wore similar clothes and a brown anorak.
Police appealed for anyone with information about the incident, which happened between 1900 GMT and 19.35 on Friday, to contact the incident room on 029 20527267, or Crimestoppers on 0800 555111.
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