I built a nesting shelf from these plans
https://dnr.maryland.gov/wildlife/pages/habitat/warobin.aspx
and mounted a Blink camera inside. It works great and an American Robin has been building a nest in it the last few days. She appears to be done with the mud and has been lining the inside with grass. Well, earlier today, the camera caught a House Sparrow in the nest. The Robin quickly chased it off but how persistent are Sparrows? Do I have to worry about them coming back and harming the Robins whenever there are eggs or baby birds in the nest? The male Robin has been great at chasing Grackles out of the yard; maybe he has it handled well and I shouldn’t intervene with the Sparrows? Located in the central US, no bird feeders and the nesting shelf is mounted around 10’ off the ground under the eave of my house. The Sparrows have been hanging around my yard and appeared to be interested in the nesting shelf; but catching one on video in the nest confirmed their interest in it.