This Shabbat is called Shabbat Shira, the Shabbat of Song. The newly freed Israelites sang a beautiful song after crossing the Red Sea thanking God for saving them.
There is a custom to leave food for birds outside our homes on this Shabbat. Why? Chirping of birds is the way that birds praise G-d. On this Shabbat we thank them for teaching us to sing praises to G-d.
The second reason: The Torah says that in the desert the Jews ate manna, a gift that God sent them every day. But on Friday, everyone was to pick up two pieces, so that they would not need to gather it on Shabbat. The first Shabbat in the desert some Jewish rabble rousers got up very early and put manna out on the ground. When everyone would wake up and see the manna, they would distrust what God and Moses had said. But birds came and ate it before everyone woke up and the plan failed. So we repay the birds by giving them food on this Shabbat..