A three-year-old fell out of the upper window of this Evergreen home. (CBC)Paramedics are again warning parents and caregivers to secure windows around small children after a boy fell out of an upper floor window of his Calgary home in the southwest neighbourhood of Evergreen.

The three-year-old was taken to the Alberta Children's Hospital in serious condition on Sunday night. The boy was playing with his older sister on a bed, when he leaned against the screen of an open window and fell several metres to the ground.

The boy's mother told CBC News on Monday that he is now awake and breathing on his own and doesn't appear to have broken anything.

"The young patient does fit the profile of the demographic that is most prone to sustaining this type of incident in the home," said Stuart Brideaux, a spokesman with Alberta Health Services emergency medical services in Calgary, on Monday.

"We naturally think of opening a window to get fresh air … when the evenings are warmer, but open windows do present a serious safety hazard for young children, particularly children ages one to four."

He recommended that parents install devices that prevent windows from opening more than 10 centimetres and not assume that window screens are sturdy enough to keep a child from falling through. Brideaux also advised that anything a curious child can climb onto should be moved away from a window.

This is the second time this month that a Calgary child has been sent to hospital after falling out of a window. On May 4, a two-year-old girl tumbled about six metres from a second-storey window at her McKenzie Towne home to the concrete below.