Now, the fact that his landlady appeared to be slightly off her rocker didn’t worry Billy in the least. After all, she was not only harmless – there was no question about that – but she was also quite obviously a kind and generous soul. He guessed that she had probably lost a son in the war, or something like that, and had never got over it.

This quote concerns some of Billy’s initial impressions of the landlady, and it is the only time the cause of her mental instability is directly discussed. It is highly significant because it proposes a connection between grief and psychosis: the root cause of the landlady’s insanity is the loss of a loved one that the landlady was unable to process or accept. There is no direct evidence of the landlady’s loss, and the suggestion remains only speculation on Billy’s part. However, such loss and resulting grief was common in England during the post-War period, and therefore this cause of her psychosis stands as a logical possibility.

“That parrot,” he said at last. “You know something? It had me completely fooled when I first saw it through the window from the street. I could have sworn it was alive.”

“Alas, no longer.”

“It’s most terribly clever the way it’s been done,’ he said. “It doesn’t look in the least bit dead. Who did it?”

“I did.”

This exchange between Billy and the landlady toward the end of the story makes clear the reason why the landlady commits her awful crimes. Rather than express sadness at the death of her parrot, she frames it as sadness that it is no longer alive. The difference is subtle, but significant. It shows that the landlady has a difficult time accepting the death of the people and animals she loves. Instead of grieving and moving on, she copes by meticulously taxidermizing them to keep them around, or she may even pre-empt the sadness of their natural death by precipitating an unnatural one herself.