There seems to be a pair of swallows trying to get into my huose/garden ¿How do i stop them?

Hi! I have a fenced garden where my cats hang out most of the day, its been great for them all the sun and grass none killing wild animals or getting into traffic.

Most of the birds around here avoid my garden since the cats are very visible and even "chirp" at the birds to lure them in, horever juts a few weeks ago a pair of swallows keep perching at the top of the fence, sometimes flying really close to my door and the ground and  im afraid my cats are going to eventually get them.

More worrisome, this past week one of my cats catched one when its was trying to get into my home (Why this?),  we managed to make the cat drop it and it flyed away without much trouble.

So my question is, how can  i keep them away from my house? or why are they so interested in my house aniway, i hoped the close encounter with my cat scared them away, but they keep coming back. I dont want my cat to hurt them; since they are a pair my guess is that they want to nest here. (why? Every other bird knows there are cats here!)

PD. English is not my first language, so i hope everithing makes sense

Thanks in advance!

PD. 2: Also, sorry if there is a cuestion like this, i will undertand if ou just post  a link and tell me to delete the post!