2. Water
A low elevation bird baths is the best as it offers enough space for them to bathe and drink. You’ll want to set the water in the bath so that it is two to three inches deep. This is because cardinals are large enough to bathe in waters that deep, but it’s not so deep that they feel uncomfortable.
The next step is setting the birdbath out in the open so that the cardinals will see it as they fly over your yard. A good open space will do and not very far from the food source. Keep in mind that cardinals may still not see the bath, so you might want to add a dripper that creates ripples in the water which will attract their attention.
The birdbath should also be on the ground as cardinals will often forage in the grass for their food. During the winter months, adding a heater to the birdbath will keep the water from freezing which means that you can enjoy the company of cardinals the year-round. Once you have set up the food and water, it is time to provide the cardinals with some suitable shelter.
Running water is an enticing prospect for any Cardinal. They can bathe and drink from it but more importantly they seek out your yard using the sound of running water. This is why I’d always advise to get one of these solar powered fountain pump that turn your bird bath into a running water fountain with only the power of the sun.