That's fun, I didn't know Blijdorp did a pride event!
This is an easy one, as it must be June 2023. The Himalaya enclosure visible on the map opened in July 2022, and early 2024 they switched from their continental map to their "future vision" map, which has the names of the regions from their future masterplan rather than the names of the continents. Seeing as it's pink and there's multiple gay animals highlighted, it could only be June 2023
Thanks for your help @Mr Gharial in identifying a couple of the dates on my zoo maps that I recently uploaded into the gallery. This pride event map is unique in my collection of almost 3,000 different zoo maps as I've literally never seen another map like this one. However, I wonder if Blijdorp Zoo ever had another rainbow-themed map in another year.
@snowleopard The only other zoo I've seen do a pride event is Artis, who had a float in the "Canal pride" parade in Amsterdam a few years ago. It's kinda strange not a lot of zoos do pride events, since there's a lot of "pride behaviour" in animals (the highlighted animals on the map being only a few examples)
