Bewildered!

So I'm in my kitchen last evening preparing supper, and little Gracie is doing her favorite thing (other than sleeping on my bed) which is sitting in front of the glass door looking outside, and all of a sudden she starts barking, so I go to see who is at my door. Now this is only about the third time I've actually heard Gracie bark, so I figure it must be someone pretty important, but when I look out, no one is there. So I go back to the stove, and she starts barking again; so I go back to the door and look out, but I can't see anybody, and then I notice what it is she is barking at...can you guess what it was...a hummingbird! The crazy dog was barking at a hummingbird that was feeding from my flowers! Cars go by, people come to the door, dogs bark, and she never makes a peep, but when she sees a hummingbird she goes crazy! Go figure....