I've been questioning the subspecific clasification of the zebras at Madrid for quite some time, and your post where you can see a bit of the sign for the species (which I didn't notice in my visit, maybe they are new signs?) make me want to expose my thoughts to fellow ZooChat users.
The zebras at Madrid look a lot more like Chapman's zebras (Equus quagga chapmani) like the sign at the park suggests rather than Burchell's zebra (Equus quagga burchellii), which is the subspecies both the zoo's website and Zootierliste claim to be living at the zoo. Many spanish zoos that have housed common zebras of any subspecies as well as zoomix individuals have laveled their zebras as "Cebra de Burchell", as Equus burchellii was once a valid scientific name for the species.
What do you guys think? I've been thinking this ever since I saw these zebras with my own eyes earlier this year, you can perfectly see the stripe pattern on this picture witch matches way better with Equus quagga chapmani.