Beaks, Butts, and Bird Behavior

Lesser Goldfinch

Lately my yard has been full of little yellow birds. The Goldfinches I am familiar with, but what happens when your yard is suddenly infiltrated by other little yellow birds? This happened to me recently and suddenly I found myself with a fun birding challenge! The bird above is a Lesser Goldfinch and is a daily yard bird for me here in Tucson.

Tennessee Warbler in my Tucson yard 10-22-2012

Last month I had a new yellow bird show up in my yard. I knew it was a warbler because of the way it behaved and the shape of its beak. While a goldfinch has a stubby cone-shaped beak for eating seeds, a warbler has a thin pointy beak for eating insects. The warbler also has a totally different posture than the Goldfinch. While a goldfinch sits more upright on a branch, the warbler has a more horizontal posture as it looks for insects beneath the leaves. When I saw this yellow-greenish-gray warbler in my yard with a hint of an eye line and no wing bars, I thought at first that it was an orange-crowned warbler, which is a species commonly seen here in Arizona. However, as I did further research I discovered it was NOT and Orange-crowned warbler, but a far out of range Tennessee Warbler! How did I know this? Well, this is where the "butts" come into play. If you look at this photo you will see that the feathers underneath the bird's tail are white and not yellow. These Feathers are called "under tail coverts" and are a key field mark in identifying some species of birds. I learned that Tennessee Warblers look very similar to Orange-crowned Warblers except for their WHITE and not yellow under tail coverts. 

Orange-crowned warbler in my Tucson yard 10-23-2012

However, the next day an Orange-crowned Warbler DID show up in my yard! Here you can see its thin pointy bill and its yellow undertail coverts. Another distintion was the way the orange-crowned warbler behaved. it was much more active and flitted around the yard making a "tisk" sound like a yellow-rumped warbler does. I first heard this bird, then went outside expecting to see something different and I did!

Orange-crowned Warbler in wild Tobacco Bush

Here is the Orange-crowned warbler before it popped up in the open. While you see its yellow undertail coverts how do we know it is not a Lesser Goldfinch, which also has yellow undertail coverts? Because a Lesser Goldfinch also has a notched tail.

Orange-crowned Warbler

Compare the thin pointy beak of the Orange-crowned Warbler above with the thicker beak and the notched tail of the Lesser Goldfinch below.

Lesser Goldfinch in my Tucson Yard

Now, if you live in a part of the country that has both lesser Goldfinches and American Goldfinches, how do you tell them apart? Once again it is the color of the undertail coverts. When goldfinches are in full breeding plumage it is a bit easier to tell the males apart, but the females and the winter plumage can be a challenge. One thing that stays consistent, however, it the color of the undertail coverts. In the lesser they are yellow, while in the American they are white!

American Goldfinch, Andover, MA April 2012

Here is a female American Goldfinch with white undertail coverts!

American Goldfinch, Andover, MA  April 2012

This male American Goldfinch is molting into his breeding plumage. Notice his bright white undertail coverts!

Yellow-rumped Warbler (Audubon's) Tubac, AZ 2009

Then, on October 30 I had another bird in my yard that was different  I first noticed it because of its behavior. It was flitting around on my small piece of lawn acting like a flycatcher. I knew it was not a sparrow or a goldfinch because of its behavior. I suspected it might be a yellow-rumped warbler because of its behavior! A quick look through my binoculars proved that it was indeed a Yellow-rumped warbler! I was so excited because this now made three warblers for my new Tucson Yard Life List! Notice that this yellow-rumped warbler has streaky side, yellow flanks, a broken eye ring and a yellow spot right above its tail. This is where this species gets its name and it is one of only a few warblers that has a yellow rump.

Yellow-rumped Warbler, Tubac, AZ 2009

Yellow-rumps are also affectionately known as "butter-butts" due to this field mark. Yellow rumps are divided into two distinct sub-species. there is the Western "Audubon's" variety and the Eastern "Myrtle" population. To distinguish these two varieties you do not have to look under their tails however...

Yellow-rumped Warbler (Myrtle) Andover, MA October 2011

All you need to do is look at their throats! Myrtles have white throats while Audubon's Yellow-rumped warblers have yellow throats as well! Birding is Fun because we can learn how to identify species by the shape of the bird's beak, the color of its under tail coverts and the bird's behavior! Beaks, Butts and Behavior, they are all part of birding and Birding is Fun!

The End!

To visit my other blogs please click on the links below:

• Kathie's Birds
• Kathie's Poet Tree
• Sycamore Canyon
• Sycamore Canyon Birds