Project LIFE Energy as implemented in thirteen SPAs (Special Protection Areas) in the period of 1st September 2014 - 31st December 2019 and was aimed at protecting the ten priority bird species. Project pages are currently updated only on an occasional basis.
Birds (many of them) have the ability to see UV (ultraviolet) light, which we humans cannot see.
The following graphic illustrates that by comparing our (rather limited) human spectral range to the larger one birds have, including UV (ultraviolet), based on them being tetrachromats (they see 4 colors: UV, Blue, Green, Red approx. 300-700nm), whereas we humans are trichromats (we only see 3 colors: Blue, Green, Red, approx. 400-700nm).
Be reminded: The pink-magenta UV "color" shown here has been chosen to make it better visible for us humans, it is a "false color", as per definition UV light (approx. 300-400nm) has no color!
The entire original article can be found here.