Self-seeded sunflower seedlings

I've noticed a lot of sunflower seedlings around the plot this week - some in areas where I didn't grow sunflowers last year, so they must be from the neighbour's plants. 

I'm leaving them deliberately to see how long they survive. If I sowed sunflowers this early, they'd get decimated by slugs in no time so it'll be interesting to see if self-seeded seedlings fare better!