A local gardener was commenting recently that he believes providing fresh water for wild song birds in the summer is better for the garden than providing seed. Why? "Because fresh water attracts the birds into the yard, then after they arrive, they stick around, dining on garden pests." The theory is that if you provide seed for the birds, they will eat what's easiest rather than spend time searching out and ridding the garden of the unwanted pests.
Of course, if you do want to provide seed for the birds, too, a fun way to do this is to grow lots of sunflowers and other seed producing plants, enough for everyone to get their fill. (Local birds also love grapes and tree ripened fruit!) Well seasoned gardeners often plan ahead so as to grow enough plants to be able to provide "sacrifice plants" grown especially for the wildlife that might visit from time to time. Gardeners will even do this for certain types of insects, like the beloved "Tomato Horned Worm" (the caterpillar stage of the local Sphinx Moth) that loves to eat tomato plants when the leaves of the plant are at their tenderest. When found, instead of killing the caterpillars, such gardeners will transfer the insects to a tomato plant that has been tended especially for them.
If you do provide water for birds, make sure to refresh it often.