The illusion was very strong on my mobile screen and non-existent on my desktop screen. The screen calibration was different in the latter I believe so the pigeons were appearing as a slightly different colored grey blocks visually distinct from the vertical bars.
On my laptop, I am only able to see the illusion if I looked at the striped background and blur my vision a little. Then it is quite impressive and strong. Otherwise, it always appears perfectly smooth for all colors.
