What was unusual about pictures taken in 1907 by German photography pioneer Julius Neubronner?

Amazingly it was a pigeon camera designed to be carried strapped on what it says...a pigeon! Julius Neubronner designed the camera so he could see what flight was like for the birds so he strapped it onto his own pigeons with a timer to take pictures while in flight. Cool stuff! Of course, the revolutionary technology was soon applied to surveillance.

https://www.newyorker.com/culture/photo-booth/the-turn-of-the-century-pigeons-that-photographed-earth-from-above