During the hot and often dry conditions that make up the “dog days of summer," you will be doing yourself and your birds a big favor by providing them with a reliable source of water.
Water is very important to birds. Whether they are feeder visitors or not, birds need water. Offering a dependable source of water is probably the simplest and most important step you can take to greatly increase the variety of birds in your yard.
It can also significantly increase your enjoyment of your birds by allowing you to watch their often comical antics as they drink, bathe and preen.
However, as entertaining as it is for us, water (or the lack thereof) can be deadly serious for birds. Birds must be ready to fly at all times, and bathing is a critical part of feather maintenance and staying in top-flight condition.
Water is also vitally important when it's extremely hot and a bird’s ability to regulate its body temperature can become stressed. Birds do not sweat and must remove excess body heat through their respiratory system. So when temperatures rise, a bird's respiration rate increases, sometimes to the point that it can be seen panting like a dog. This activity dehydrates birds and increases their need for a reliable source of water to replace lost fluids.
So, while the addition of a bird bath, fountain or mister to your yard can supply hours of enjoyable bird watching entertainment for you, it may also be providing a lifesaving necessity.