Thats specular lens flare (ghosting), it looks like multiple little dots here, instead of a larger dot, since the light is partially blocked by tree branches. A lens hood and repositioning the camera are the only ways to prevent these.

Must be of alien origin, the glow matches the green shown in documentaries.

I think it must be a speck of something on my lens. There's a similar artifact on another photo I have from around the same time, in about the same light.

Thanks!