I've been having my breakfast and morning coffee at our backyard picnic table of late in part to watch the hummingbird show.

The black-chins have been around since April, but the real drama began last month when the rufous hummingbirds arrived. The rufous are incredibly aggressive, and highly territorial. At any time right now, there's a rufous somewhere in and around my back yard, usually sitting up on the power line along the back fence or on the top branch of our little apple tree, waiting.

They don't spend a whole lot of time around the feeder, but woe to the other hummingbird that strays in. The rufous zooms down in an aggresive display of dominance, driving away any other bird that thinks it wants a drink of our sugar water.

That zooming flight marks one of nature's remarkable outliers. Hummingbirds have the largest hearts relative to their body size of any vertebrate creature and the most amped-up metabolism.

Now, thanks to the work of University of New Mexico ornithologist Chris Witt and a group of colleagues, we know another one of those "-ests" that we science journalists love when we're trying to pursuade our editors to put something in the paper: hummingbirds have the smallest genomes of any bird. Period.

This odd fact made sense to me once Chris explained it. One of the characteristics of hummingbirds' superlative metabolism is tiny blood cells, the better to move oxygen to muscles in a hurry. (It's a surface area-to-volume thing.) And genomes simply take up a lot of space in cells.

But here's the best part for my journalistic marketing. Of the 37 (corrected) 116 hummingbirds representing 37 species Witt and his colleagues studied, the absolute smallest genome belonged to a black-chin caught in Witt's back yard, in Albuquerque's northeast heights not far from UNM (and coincidentally, not far from my house).

More in tomorrow's newspaper in the newspaper some time this week, along with more nice hummingbird pics by Journal photographer Richard Pipes (who took the shot above) or you can aread the technical details in the paper Chris and his colleagues published last week on their findings, or read Rachel Ehrenberg's piece on the research in Science News.