If people refuse to bring their pets in, call the police. While it may not be illegal to keep pets outdoors in the winter, it is illegal to do so without making sure they have proper shelters.
Whether you’re an avid birdwatcher or you’re simply an animal lover who wants to help all species survive, there are steps you can take right in your own backyard to make the winter season a little more bearable for the birds and mammals that frequent your outdoor space.