Artificial Migration Routes for Monarch Butterflies

Something about the previous post reminded me of a project by Elliott Malkin called Graffiti For Butterflies.

[Images: Graffiti For Butterflies by Elliott Malkin].

Graffiti For Butterflies attempts to "direct" monarch butterflies "along migratory routes in North America," using "images of milkweed flowers to broadcast the location of food sources."
Malkin applies sunblock to these images in order "to optimize the graffiti for butterfly vision." He calls this Urban Interspecies Communication.
Overlooking the most basic question here – of whether or not this would actually work – the very idea that we might deliberately construct an alternative visual system inside our cities, legible only to other species, is totally fascinating. What devices of route-finding and navigation could we purposefully produce for non-humans?
Is there a burgeoning field of graphic design for other species? Post-human signage and symbology?
There are already olfactory labyrinths left behind by dogs, for instance, and there are accidental but extraordinarily complex sense-trails following us everywhere – from food scraps to automobile exhaust to whiffs of perfume on the subway – but what deliberate "graffiti," otherwise undetectable by humans, could we create in order to help other species navigate the urban world?
Using special UV paints to mark artificial migration routes across the continent seems like an amazing way to begin the investigation.