Too much glass

Assuming that Google and dusty memories have excavated basic trig correctly for me, the about fifteen degree angle to the very wide glass in the patio door, which I can presume to be two layers of 7mm float glass, means these are going through 27mm of glass, twice, with an internal air gap.

Which does rather explain the regular vertical streaking in the full sized versions of these, and the what-is-going-on-with-that-lens? effect. The lens is fine; it has no way to prevent the photographer from over-reacting to a cardinal that will hold still and trying to shoot through what amounts to four Coke bottle bottoms.

Looks like he'd really like to be able to come in there and thump me a good one, doesn't it? Doesn't mind the oilseeds, though, even if both he and Mrs. Cardinal are tremendously shy on the feeder.