Last week, I wrote about the different types of bird baths you could buy, but we’ve gotten some questions on the ideal depth of a bird bath. Should it be deep or should it be shallow? The easy answer: it depends.
Finding the ideal depth of a bird bath is kind of like trying to figure out whether Coke or Pepsi is better. Some birds prefer it one way and other birds prefer it another way. Most common backyard bird baths have a depth at less than 2 inches at its lowest point (usually the middle), which works for many species.
If you’ve watched birds in waters around streams and lakes, you’ll notice many of them staying in very shallow waters. Small birds are frightened by deep water and will refuse to go in while larger birds prefer water with more depth.
A good rule of thumb to follow, as laid out by the National Audubon Society, is that a bird bath with a 2-inch depth is ideal for larger species like Northern Cardinals, Grackles and Blue Jays. Smaller songbirds will go in depths at about 1 inch. Many bird baths give some flexibility because they aren’t the same depth throughout the entire bowl. Larger bowls have slopes that give the bath various depths. This would be able to accommodate larger and smaller birds.
If you happen to get a bird bath that’s much too deep and you’re noticing not many birds are using it for more than drinking, you could add large rocks to mimic the natural setting of lakes. The bird bath in the image above is likely much too deep for many birds, so having stones will help them see the bottom and be more comfortable preening in it. So even if you have a bird bath that’s too deep, you could easily fix it.
After you buy a bird bath, you should monitor it to see whether birds are actually using it for drinking and preening and make improvements based on your observations.