Close-up - from a distance

I was playing with my long lens this morning (150 - 500mm) intending to photograph birds. Birds were not immediately forthcoming, the dogs were all sitting or lying around - quite still, looking at me but not anticipating anything exciting. Just to remind myself what the lens could do I turned the camera on the dogs at full 500mm. Wow!  I couldn't get the whole head in, not even Pixie! (I was about 12ft away) The focus was on the eyes, naturally, and with the aperture set at f7.1 the depth of field was quite shallow but even so the detail in the noses and hair is acceptable. The birds?well I did get a couple of Starlings - one in the extras.