On MIT APP INVENTOR BLOCK CODE

I'm trying to make my image sprite which is a bird go somewhere else like for example the bird is going left and after it reaches the end of the screen I have another image sprite which I call end which is at the very left of the screen and another one called start which is at the very right of the screen. So I want the bird after it reaches the END I want it to then teleport and start back at START so it'll loop forever.