There was an I nteresting article on the radio news this morning regarding counting Northern Royal Albatrosses on the remote and mostly inaccessible Chatham Islands off New Zealand. Using the latest NASA technology, ultra high resolution satellite images, they can accurately count objects as small as 30cm across, good news for conservation purposes as it has already revealed a stable population of the Albatrosses on one of the islands.
This has potential for counting the populations of larger birds, mammals etc in other remote areas of the world, presuming if they aren't in hidden or obscured locations. I've found the link from the Independent.

http://www.independent.co.uk/news/science/albatross-space-numbers-count-space-satellites-chatham-islands-birds-northern-royal-digitalglobe-a7716806.html?amp