UDVWd21odkw2dFk=
3564x2256 Map
http://i.imgur.com/i2rDUO5.jpg
Pigeons 51-100
https://www.youtube.com/watch?v=WS1P5hzBlvQ
Don't look at how many birds I have remaining. I killed my first bird out of order, which is why it says 198 birds left after my first kill. If you simply follow all 4 videos and use the map with the number I placed on the video for each kill, you will find all 200
This video contains the locations of pigeons 1 through 50 as detailed on the map above.
Killing all the flying rats will get you the Endangered Species achievement
Map taken from MSxbox-world and Gamesradar