LOS ANGELES - Wild kittens that will number in the tens of millions this year are starting to be born, and overtaxed shelters will be forced to euthanize most they receive. It is a grim reality a leading advocate calls "one of the last major problems" plaguing the animal welfare movement.

Scads of people who discover wild litters of baby cats will take them to shelters, which are overrun with the animals. The facilities turn to euthanasia when their limited resources are stretched even thinner by the massive influx of kittens and babies that require round-the-clock care. But groups that trap, neuter and release feral cats and shelters that are able to open 24-hour kitten nurseries are doing their part to stem the deaths.

"The problem of community cats dying in shelters is one of the last major problems we in the animal welfare movement are tackling," said Gregory Castle, CEO of Best Friends Animal Society, a leader in the no-kill movement that runs the largest animal sanctuary in the country.

He says "there's a ways to go" but has seen a dramatic drop in deaths whenever his group connects a shelter with a local organization that traps, neuters and releases free-roaming cats. Wild kittens socialized early enough can be great pets, his group says.

A staggering 40 million feral kittens will be born throughout the country this year, but 20 million of them will die at birth, said Becky Robinson, president of Bethesda, Md.-based Alley Cat Allies.