What would happen if you were to set a cat loose among the pigeons? How do you think the birds would react? They would be pretty worried, wouldn’t they? The presence of the cat would create a great deal of disturbance. When you set a cat among the pigeons, you say or do something suddenly or unexpectedly. This often leaves the people worried or angry. It is also possible to say, “put the cat among the pigeons.”
*The principal set the cat among the pigeons when he informed the students that the annual day was likely to be cancelled.
S. UPENDRAN, The Hindu- ‘Know Your English’ Series, March 7, 2005
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KYE 
Dear Sir or Madam,
Thank you for the bee’s knees explanation of the idiom, I got a decent understanding of the meaning and usage of that.
Now you scratch my bag, it’s my turn to scratch yours.I would like to let the cat out of the bag that Japan’s Prime Minister Kan Naoto has been setting the cat among the pigeons unskillfully managing not only bringing political turmoil but showcasing what his party does to tackle the current earthquake disaster is lame.
Sooner or later, without doubt he would be sacked due to the plunging supporting rate for his Democratic Party of Japan.
Hope you grasp some knowledge of a current turmoil in my country.
Thanks a lot
Taka