What are the mopheads for?

[UtterlyUnimaginativeUsername]

These are in two separate gardens. Any ideas?

Drug dealers?

Two competing ones next door to each other? Or customers signalling their readiness to buy? Though I've met the people from one of those houses and either scenario is massively unlikely, they are some of the most aggressively respectable people I've ever met.

Keeping the birds away.

Scaring crows I think?