We interrupt our adventures in lifted arithmetic optimization for a brief public service announcement on behalf of my little friend to the left there. (Click on the image for a larger version.) I took this photo1 at my home in Seattle this past Sunday, before I flew down to San Francisco for training at Coverity's head office. Amazingly enough, male Anna's Hummingbirds like my friend there will spend winters in Seattle. At the time this photo was taken it was well below freezing. Apparently more and more male hummingbirds are staying in Seattle over the winter, as climate change makes the winters here slightly more survivable; even Rufous and Allen's hummingbirds are being observed.
Hummingbirds are always within mere moments of starving to death and in the Seattle winter there are far fewer sources of food than other times of the year,2 so if you've got hummingbirds coming to a feeder,3 keep it stocked. Take it in at night; I found my feeder frozen solid and a very vexed hummingbird trying in vain to feed one morning.
You'll notice that in my feeder the liquid is clear and colourless. It is one part sugar to three or four parts water, and that's it. Stores will try to sell you hummingbird food at enormously inflated prices, but what they're selling is sugar mixed with red dye. The red dye does nothing to attract the birds, and it is bad for them. Their little kidneys have to remove the dye from their bloodstream.
I'm in California again next week, but I've queued up a couple of articles to go out while I'm away. Have a great weekend, and tune in Monday for the final episode in my excessively long series on lifted arithmetic optimization.