Saskatoon police want the mother of a newborn baby girl found abandoned in sub-zero temperatures to turn herself in to authorities.

A police spokesperson said Sunday that they are concerned about the mother's health. They also want to know how the three-day-old baby came to be abandoned on the doorstep of a northwest Saskatoon home Saturday morning.

"We have -- chances are a very young mother here -- a very scared new mum here," said Alyson Edwards of the Saskatoon Police Service.

"We want to assure her we're not going to throw the handcuffs on and throw her in jail. What we want to do is work with her, to find out what were the circumstances leading to this."

Saskatoon resident Ed Anderson stumbled upon the girl, who was wrapped in a towel and sleeping bag, as he headed out the back door to start his vehicle in temperatures that dipped to around -29 C.

"Right down here was a little bundle between me and the car," he told Â鶹´«Ã½.

"There's not a lot of room here, and I reached down to move it, heard a little squeal and realized immediately it was a little baby."

"At first I was shocked; emotions went into high gear. I mean, you've got a vulnerable little baby, it's minus 29. So we had to take care (of her)."

Anderson's wife, a registered nurse, cared for the child, who was still covered in blood and mucus. She warmed the infant up before emergency workers arrived to take her to hospital, where the seven-pound girl is recovering and reportedly in good condition.

"They noticed the baby still had the umbilical cord ... and it's hard to tell even what nationality it was," said Troy Davies of MD Ambulance about the paramedics who attended.

Anderson credited his dog Pica with alerting him to the baby's presence. Had the dog not been barking, "then I'd come out 10 minutes later to start the car," he said.

Anderson says he's not sure why the mother chose to leave the baby at their house.

"Well, I think it was random. It had to be," he told Canada AM. "We're on a block with four other nurses on our street alone -- one who, three doors down, is a neonatal nurse. So there were better choices in the community. But I think it was random. The mother probably was in distress and confused and chose us."

Edwards described the baby girl as "extremely lucky." She said an investigator will be following up leads in the case, adding the priority is to find the child's mother.

The baby's mother could face charges in the case, depending on what those circumstances are, she said.

Police officers canvassed the neighbours to see if anyone can provide information on the girl. A dog team tried to find a trail leading back from the Andersons' home.

With reports from CTV 's Mark Rogatch and files from the Canadian Press