Their little bellies get in the way. At my old house i used to watch them do " daycare". I think i have a video. Its Robins, Doves, AND a freaking blue Jay baby! The first 2 are compatible, and the mothers fly in only to aid in helping them occasionally. The blue Jay puts everyone on ⚠️ alert. 🙃 It's like when that one trashy family shows up at a wedding, and you just know somethings going down lol😂 I love nature. ❤