The RSPCA in Swansea says it is seeing an increase in the number of abandoned cats and kittens it's taking in.
Staff there described this year as the 'worst ever' for the problem and said they're struggling to cope.
The problem stems from cat owners being caught out when their un-neutered pets have litters.
Now the society is working with Cardiff University to try to establish why owners aren't taking preventative measures.
More top news
Rain overnight turning light and patchy in the morning.
Most of us will have a pleasant and dry evening with a few late sunny spells, though the odd light shower is possible.
The Eisteddfod's intention to visit an area must be proclaimed at least a year and a day before the beginning of the festival.