The Black-chinned Sparrow has a lovely song. Take a listen. If it sounds familiar, that is because it is very similar to the song
of the Field Sparrow, our songbird for April 24. They are very closely related,
either closest relatives or nearly so. But, unlike most very close relatives, they are not quite ecological equivalents. The Field Sparrow
nests in old fields in eastern North America; the Black-chinned Sparrow nests on brushy canyonsides in western North America. Neither
of these habitats exists in the other region. Also, they don't look alike, except for the pink bill. The Black-chinned is an outlier in its genus,
Spizella. Click its name in the eBird box and you will see a pretty picture.
Now, about these lovely songs. The more you know, the more you see. The more you see, the more you feel. I just learned something else
from Pieplow, page 435 in his western guide. He says every male has at least two song-types, one with all the notes rising in pitch, the other with
all the notes falling. That in itself is a remarkable thing. The birds actually must pay attention to whether those slurs are upslurs or downslurs.
Think about that when you listen to the Northern Cardinals that are ubiquitous in many areas, because they use steep upslurs and downslurs, too.
Please note that we have both types in our sample. Also, that each upslurred song has an intro note way out in front, and then a strange little broadband
note right before the main song. Then, one of the downslurred songs has two long pure whistles at the beginning. All the others of this type follow
so hard on the other song-type that there is no room for these whistles. In my experience, such whistles are common parts of black-chin songs.
And now for the big reveal. Nathan says they frequently alternate their two song-types. No big deal there, but in our sample the two song-types are jammed
together. I thought this was two rivals in a song-duel. Song-duellers in other species often match song-types. Here they are doing the opposite.
But, the two song-types do not overlap. The second is begun immediately after the first one, seamlessly. It is possible this is two birds in an unusual
type of duel, but it seems a bit more likely that it is one bird, alternating his two song-types in tandem, with no space in between. I have never seen
that before. Wow. Thank you, Nathan.