OAKLAND (KRON) — The number of kittens surrendered to the Oakland Animal Shelter is up 38% from this time in 2014.

Unfixed female cats go into heat during the summer as the weather gets warmer, and the region’s drought combined with warm winter weather has led to the surge in kittens abandoned at the shelter.

That increase is upsetting for shelter officials because “kitten season” has just started and will run throughout the summer.

Because of limited space at the shelter and also a high need of care for the small kittens, Oakland Animal services is asking residents to help foster. “We need help from the public to foster all of these kittens who are too young to survive at the shelter. Once these kittens are old enough, they can be fixed and adopted into loving homes,” Rebecca Katz, executive director of Oakland Animal Services, said in a statement.

Kittens brought to the shelter without their mothers must be bottle-fed or fed by another mother cat in order to survive.

Residents can foster a kitten through a rescue group that partners with the OAS. For more information, people can join the shelter’s upcoming free class about caring for kittens by emailing volunteer@feralchange.org.