Window Bird Tape

My wrap around porch windows are a killing ground for birds, mostly doves. The windows reflect the sky and trees and the birds think they have an open flight path.
Ideally if this was new construction I would use the specialty Ornilux glass that is opaque to birds but transparent to humans.
 I purchased a few rolls of bird collision deterrent marker tape from Feather Friendly a Canadian Company. The tape is non distracting and has cut down on the casual window bird collisions where birds mistake the windows for sky. However, the gray hawks have learned to chase doves into the windows and then swoop in and take the stunned bird. I see this on many occassions and recently saw parents teaching a chick this hunting technique.

Here is an inside looking out section of windows prior to installing the tape:

 

 Here is the inside looking out view after the bird tape has been installed:

The small squares are barely noticable and after you get used to them you don't even notice.

Here is the outside window view:

 

The squares are applied to the outside of the window and are therfore more noticable.   These have been on since 1Nov2014 (~2.5 yrs at the time of this post) and even with window washing they have remained intact.