Meet the White-crowned Sparrow

Now it's time to meet the star of the show: the Nuttall's white-crowned sparrow (scientific name: Zonotrichia leucophrys nuttalli)

Photo by K. Schneider on Flickr

White-crowned sparrows are quite common and found all over the United States. However, even though they are all the same species, they are divided up into five different subspecies, determined mostly by migration patterns. The three we get here in San Francisco are Puget Sound (known affectionately by their four letter banding code as PSWS or "piss wiss"), Gambel's (GWCS) and Nuttall's white-crowned sparrow (NWCS).

Of the five subspecies, NWCS, is the only one that is non-migratory. Since they don't move very far from where they were hatched, it is easier to determine where they picked up a parasite.

The songs of white-crowned sparrows have also been extensively studied. Unlike birds with repertoires like mockingbirds, white-crowns sing a single song type. However, within that one song type there are many variations (Baptista 1977). When learning about birds and specifically bird song, white-crowned sparrows are always brought up as the classic example of song dialects. Dialects are like accents in human communication - they're "speaking the same language" just with different inflections. Juveniles learn to sing by listening to their fathers and male neighbors (DeWolf et al. 1989) and females preferentially mate with males singing the dialect they grew up hearing (Baker 1983). Thus the dialects are reenforced.

Even within the same subspecies there are populations that sing different dialects. Here's a map of San Francisco showing three different Nuttall's dialects recorded in 1975:

Luther, D., and L. Baptista (2010) Urban noise and the cultural evolution of bird songs. Proceedings of the Royal Society B: Biological Sciences, 277(1680): 469-473

The diagrams on the left are spectrograms, a visual representation of a song that graphs frequency over time.

To match the audio with the visual, this is a bird I recorded sining in Cesar Chavez Park. He was in this bush:

And here is the associated spectrogram:

And now you've met the white-crowned sparrows! You will see (and hear) many more in the posts to come. 

For some reason the word that comes to mind when I see a male white-crown is pugnacious. They kind of look angry and determined all the time. 

Photo by Anders Illum on Flickr