During the warmer months of the year, thanks to a phenomenon known as Feline High Rise Syndrome, city dwelling cats routinely fall from open windows and fire escapes, often necessitating a trip to an emergency veterinary clinic.

According to ASPCA.org:

Pet parents residing in tall buildings often allow their cats to sun themselves in open windows and on fire escapes, unaware that their felines' prey drive may lead them to pounce on moving birds or insects. Tragically, falls often result in shattered jaws, punctured lungs, broken limbs—and even death.

A few facts about High Rise Syndrome:

• When a cat falls from a high perch it's unintentional, not deliberate. Cats are smart. They don't leap from high places because they know it's dangerous.
• The reason cats fall is usually because they are intensely focused on something outside, perhaps a bird, and either lose their balance or their prey instinct sends them out the window before they realize what they're doing. Another cause of falls is normal muscle twitching and other movement during deep sleep. A kitty can roll off a window sill while changing sleep positions.
• While cats won't intentionally jump from a high perch, they also don't realize they can't dig their claws into brick, concrete or steel surfaces to help prevent a fall if they lose their balance.
• When a cat falls from a high perch, he doesn't land squarely on all fours. He lands with his feet slightly apart, which is how serious head and pelvic injuries occur. And falling shorter distances can actually be more dangerous, because kitty doesn't have enough time to adjust his body to land correctly.
• Even if your kitty survives a fall in relatively good condition, she'll land in an unfamiliar, frightening place on a sidewalk or street and can easily run away before you can get to her.