Mr Justice MacKay adjourned Smedley's sentencing to a date yet to be fixed for the preparation of a pre-sentence report, and remanded her into custody.
He told her: "I want you to understand that you stand in very real peril of a prison sentence as a result of this conviction. Don't have any delusions about it."
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Kelly Mahon, 41, was arrested on the afternoon of the "pre-planned" abduction in Telford, Shropshire on February 24.
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A number of wild baby animals have died after being illegally picked up by people thinking they had been abandoned - or wanting a selfie.