Most lost birds are hungry and thirsty.
Water is necessary before all else.
Since pigeons drink by suction, any water container should be at least 1 in. An open container, i.e., a dish, an old margarine container tub, etc., is best. While a thirsty bird may drink immediately, it also may not. A bird which has gone without water for a while is sometimes a bit less than itself. It may be so exhausted, it doesn't even realize that water is in front of it, especially if the water container you use is different from what it is familiar with.