After spotting the Cassin’s Finch (Carpodacus cassinii) pair above a couple of weeks ago at Lassen Volcanic National Park, I thought I had a new lifer! Now I’m not so sure. I may have seen these birds in my own yard and not even have known it!
There are subtle differences between the Cassin’s Finch and its close relative, the Purple Finch (Carpodacus purpureus) and more obvious differences between these two species and the other American Rosefinch, the ubiquitous House Finch (Carpodacus mexicanus).
First, let’s look at the male House Finch. Note the broad, blurry dark streaks on the lower breast and flanks which are absent in the Purple Finch and pretty much so in the Cassin’s Finch. Click on photos for full sized images.
The female House Finch has a noticeably plain face, also with the blurry streaks on the breast and flanks.
The Purple Finch is a little trickier. Let’s begin with the male again. First, note the lack of breast and flank streaking and the plump, less contoured body. This bird doesn’t have a neck like the House Finch does.
The female does however have some distinguishing marks. She has a dark cheek patch with a bordering pale eyebrow. You can see a similar dark cheek pattern in the male above. You may also have noted that the bills of both the House Finch and Purple Finch are rather large and conical shaped, similar to a Grosbeak bill.
Now let’s take a closer look at the Cassin’s Finch, and I apologize that they are not as close up as my backyard finch photos.
The first thing you might note on the female is they are more finely and crisply streaked on the back and belly than either the House or Purple Finch. More like a Pine Siskin. She also has a pale eye ring and both the male and female have a more pointy Siskinlike bill. Again, click on photos for full sized images.
Here you can see the male Cassin’s Finch is overall more trim and angular than the Purple Finch with the siskinlike bill.
He also shows the more crisp, contrasting pattern on his back and his red crown patch contrasts abruptly with the brown of his nape.
In this last photo you will notice that the male’s forehead and forecrown are conspicuously richer red than the rest of his head, and his breast is simply blushed with a pale red. That obvious and distinctive peaked red crown, I think, is his best field mark.
As Pete Dunn puts it in his excellent field guide companion, “House Finch looks like it had wine thrown in its face; Purple Finch was dipped in it. On Cassin’s Finch, the patch of red on the peaked crown is conspicuosly brighter and richer (somewhat redpoll-like)1.”
References: 1Dunn, Pete (2006), Pete Dunne’s Essential Field Guide Companion. New York: Houghton Mifflin Company