For some, tulips are the surest sign of spring. For the Ottawa Humane Society, it’s the seasonal influx of cats.

Since the beginning of May, more than 340 lost and surrendered cats have come through the doors of the OHS. This week alone, 34 cats — 15 adults and 19 kittens — arrived, leaving staff scrambling for space. Carriers with cats line the hallways until suitable cage space can be found.

“The influx of cats definitely creates a critical bottleneck situation,” said OHS director of operations Sharon Miko.

Currently, the shelter has 265 cats in the building, said OHS spokesperson Tara Jackson.

While some animals have been adopted out, others have gone into foster care until they are old enough to be adopted out or more space is available at the shelter.

The number of animals exceeds the 200-animal capacity at the shelter, which is equipped to take in 2,800 animals a year until the new building in the city’s south end is completed around this time next year. The shelter currently takes in about 11,000 animals a year.

The influx of animals is fairly typical of the season, said Jackson.

“When the weather warms up, more cats are outside and brought in by bylaw and members of the public,” she said. “We find ourselves with pregnant cats and litters of kittens.”

What’s unusual, said Jackson, is the decline in adoption numbers.

“That’s a bit abnormal,” she said.