Back in July, we had a lovely male grackle visit the bird feeders. Although grackles are fairly common around here, they don't spend much time at feeders. The light was really catching the blue and purple iridescence in this fellows feathers.
But the combined weight of the birds stretched the spring mechanism of the feeder so that the seed access holes were not aligned and neither bird could get to the seeds. This is a pretty effective an anti-squirrel device.