I guess the vireo did not sign a release for the photo
so she had to publish without it.
Sometimes warblers are actually attracted to the camera.
I've had a Chestnut-sided (juv) and a BT Blue almost look
into my lens hood. It can be frustrating when you never
seem to get close enough with a short lens and then when
something finally comes close it invades the minimum focus
(in my case 1.2 meters).