Why do babies cry at maghreb time?

I have the same issue with my 5 week old baby. He is fine all day and as soon as maghrib starts, he cries quite badly. I do the athan which quietens him down a little. I also read various ayats/verses into some water eg Surah Al Fatiha, last 10 ayats of Surah Baqarah, Ayat ul Kursi and the 3 Quls. I then spray this water on four corners of rooms. Alhamdulillah this makes him quiet!