Not that they have to do it as part of their day-to-day, but that they can communicate well enough to do so if needed. It's a given that the development skills are there in my mind, but to go beyond "junior", I believe someone has to have a strong enough understanding of things that they can both communicate well and be able to recommend solutions rather than just implement them.

Just my personal opinion. Based on environment, this may or may not be a good gauge.