Angry Birds Seasons Easter Eggs Golden Egg #13 can be found in Angry Birds Seasons Easter Eggs Level 1-7. All you have to do is make use of the white bird and drop an egg the right moment in front of the blocks which are placed behind the slingshot. It is possible to obtain the golden egg in only one shot! The image is helpful:
Angry Birds Seasons Easter Eggs Golden Egg #13 Walkthrough
And if the image wasn’t enough here is an Angry Birds Seasons Easter Eggs Golden Egg #12 Walkthrough video: