Weird 100 $ bill

[Cos17min]

I have this 100 dollar bill, 2009 a series, that has a bird on the right side on the white part of the bill. This is the only bill i found it on, i can't find another, not even online. Can anyone tell me if it's a mistake or what? Pictures below you can even see the image bleeding through the paper a bit on the other side.

[Steve in Tampa]

It’s a Chopmark. Often seen on $100 notes. 

[Cos17min]

Thank you for the reply, it was a headscrather for me, googled it and it is so, one of many marks. Thanks for the help.