This looks like the series of shelters were contructed on top of an insulated pipeline. I don’t know what the pipe carries. It is off the ground and it may be warm. Both are good reasons to place the shelters on it. It is unusual to see this which is why I published it on the site. I have to guess because we are not told that it looks like this is Eastern Europe or perhaps Russia. Someone may be able to correct me. It may be America. It’s guesswork.
The volunteers are indeed caring. There are a lot of people who are sensitive to the needs of feral cats in harsh climates. They really need help. Being made of cardboard I don’t think the shelters have a long lifespan. That’s the downside but a really nice job to have built them in any case.
SOME MORE ON OUTDOOR CAT HOUSES:
