Custom of giving birds food on Shabbos Shirah.

Some have a custom of giving birds food on Shabbos Shirah. Two reasons are given for this custom: The Aruch HaShulchan (324:3) says that since the birds sang along with us by the splitting of the sea, we help them with food for this Shabbos- the Shabbos we read about the splitting. The Nimukei Orach Chaim (324:1) explains that Moshe informed everyone in this week's Parsha that the manna would not fall on Shabbos. On Friday night, Dassan and Aviram scattered manna to pretend it fell on Shabbos, intending to discredit Moshe. The birds ate all the manna to protect Moshe, saving him unnecessary trouble. Many have objected to this custom, including Magen Avraham (324:7), Elya Rabbah (324:12), Baal HaTanya (324:8), and Mishna Berurah (324:31), among others. The objection stems from the fact that on Shabbos, it is forbidden (S.A, 324:11) to feed animals not dependent on humans for their food. There are a few ways to fulfill this custom and bypass the issue of feeding non-dependent animals: 1. Put it out before Shabbos. 2. Put food outside before Shabbos and keep it covered. Then remove the cover on Shabbos, ensuring you feed them on Shabbos itself and not Friday. 3. Feed them after Shabbos. 4. Brush off the crumbs from the meal to the birds.