The vernal equinox happens on March 19 this year, but the first poppies are already blooming and the first buckeyes are leafing out, and the finches are singing.* We’ll have more cold weather and more rain, I hope, but for all intents and purposes, spring has come to the Bay Area.

If you can spend some time outside or by a window, you might see some of those intents and purposes in action. I’m talking about “courtship,” of course, that genteel word that science applies to the behavior that animals engage in to attract mates. This includes strutting, singing, bowing, bobbing, zooming, zipping, clicking, chest puffing, feather ruffling, tail dragging, and even moon dancing. Shake a tail feather, baby. 

Color has everything to do with it, especially on males. The mallards’ heads are at their greenest, hummingbirds are flashing red, the bluebirds are stunning, and the goldfinches look like lemons on legs. On waterbirds—egrets and pelicans, for instance—the bills, legs, or lores** get more brilliant. And just because the male and female of a species look the same to us doesn’t mean they look the same to each other. Birds see colors more precisely than we do, and some, including hummingbirds, songbirds, parrots, and gulls, can see ultraviolet light. So the male and female cedar waxwing, for instance, may look equally colorful to us, but not to each other. 

Shifting to the marine world of mantis shrimp for a moment: scientists recently discovered the mechanism whereby these creatures can convert circular polarized light to a more visible form. This allows them live in a very exclusive world of color and it is now allowing us to create 3D movies and 3D-capable DVD players.***

Back in the avian world, all this conspicuous color helps a bird announce very, very clearly that he is a male. An exception is the Wilson’s phalarope—females are brighter than males and do the strutting in that species. (Phalaropes don’t usually breed around here but it has been known to happen.) The function of much of the strutting, stretching, and posing we see in everything from turkeys to goldeneye ducks is to show plumage colors to their greatest advantage. The galliform birds—turkeys as well as chickens, peacocks, grouse, quail, partridges, pheasants, etc.—are especially showy. The male sage grouse is pretty much the Elvis of North American birds. You won’t find one west of the Sierra Nevada, but you can see them in action on the Nature “What Females Want” episode. 

There’s a material aspect to courtship as well. Males may give food to females, or sticks or other nesting materials. The male bowerbirds of Australia and New Guinea build arched bowers of sticks and stems and decorate them obsessively with feathers, flowers, shells, glass, and any other bright objects they can find and carry that match the décor. The satin bowerbird uses only blue items, presumably to match his plumage. Beautiful photos of some even more beautiful bowers can be found here. 

Acrobatic displays are yet another way in which males attempt to show their genetic fitness. Hawks, eagles, kites, and other birds of prey circle each other, sometimes grabbing each other’s talons in midair, sometimes freefalling and then soaring back upwards time and time again. Hummingbirds will zoom upwards out of sight and then dive downwards, recovering just in time to not crash and burn. The trajectory of this swoop is one way to know which species of hummingbird you’re looking at. A male hummingbird in a dive looks bold and fearless to a prospective mate—and besides that, the rush of air makes his tail feathers squeak in a distinctively attractive way.

The red-capped manakin of Central and South America is another acrobatic bird that makes distinctive noises during its courtship display, but I mention it here because it is the moon walker I referred to earlier. This clip from the Nature “Deep Jungle” episode, complete with dancing ornithologist, gets astonishing at about 2:42.

Song, of course, plays a big role in courtship, and the song of the northern mockingbird, who is present all over Martinez and already warming up for the season, is one of the finest examples. Besides the song, color, and sky dancing of mockingbirds, hummingbirds, hawks, and eagles already mentioned, some other local courtship phenomena you might enjoy are the spectacular plumes of the egret (see Brian Walker’s fabulous photos right here on Martinez Patch), the sweet flirtation of purple finches, doves, and even pigeons, and the surprisingly wild dance of Clark’s and western grebes.

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* The vernal equinox will be at 5:14 UT on March 20, which is 10:14 p.m. on March 19 on Pacific Daylight Time.

** The lores are the parts of a bird's head between the eye and the upper base of the beak.

*** I got this tidbit from Roy Caldwell’s Integrative Biology 31 lectures from UC Berkeley on iTunes U—highly recommended.