Migration Mania Series #2: “Butter Butt”

Yellow-rumped Warbler rear view - adjusted lighting
A poor photo, but it clearly shows his Butter Butt!

In my first post of this series I told you all about my favorite warbler, the Blackburnian. This next one isn’t as flashy, but it’s got the best nickname of all the warblers: Butter Butt. Yes,meet the Yellow-rumped Warbler (YRW), aka Setophaga coronata, one of the most widespread of all the wood warblers in North America. As you can see, there’s no mystery to how he got his name –look at that bright yellow patch on his backside.

Front view of Yellow-rumped Warbler in spring breeding plumage
Front view of Yellow-rumped Warbler in spring breeding plumage

The eastern and western subspecies of the YRW are called Myrtle and  Audubon’s, respectively. All the photos in this post are the eastern subspecies, the Myrtle warbler. The Audubon warbler looks pretty much the same except its throat is yellow instead of white.

Most warblers have to migrate in winter because their main food source is insects. Those that migrate usually go to Mexico and Central America where they can bask in the sunshine and indulge in the abundant insect food supply. But these guys are the only warblers able to digest bayberries, so they might stay around through the winter in northern places where there’s a good supply of that food. We have some of them stay through the winter here in my home area (Oakland County, Michigan), but they’ve just started to show up in larger numbers in the past couple of weeks. Eric and I just spent the weekend birding in Savannah, Georgia, and we saw Butter Butts EVERYWHERE down there, so they’re definitely on the move.

Like most songbirds, they migrate primarily at night. I read in Birds of North America that some data indicates they fly an average of 194 miles per day in spring migration and 55 miles per day in fall migration. Either way, that’s a lot of ground to cover for such a little creature, don’t you think? At that pace, it can take them at least two weeks to cover the continental US. And when you add in weather delays (yes, airlines aren’t the only ones that are grounded in bad weather) it can probably take them twice as long.

Singing Yellow-rumped Warbler, partially hidden among the leaves
Singing Yellow-rumped Warbler, partially hidden among the leaves – this is the typical view you get of warblers high up in the trees (click for larger view)

And I learned something else very interesting about the Butter Butts while researching them for this post. You may have heard about or seen a Killdeer pretending to have a broken wing to distract you away from her eggs or nestlings, right? Well I was very surprised to read that both parents of YRWs do a very similar thing! The parent holds both wings almost fully extended and shaking, then drags them along the ground to draw you away from her precious babies. Researchers even noted one female performing this distraction display for three and a half minutes while they were checking her nest.

Here’s a link to an audio recording of the song of the Yellow-rumps (scroll down on that page), and here’s the latest eBird map of where they are now. (Darker purple indicates more reports, lighter is fewer. If you zoom in on the maps you can get down to markers that show individual reports by birders all over the country. It’s really fun to do — try it!)

I’m having a blast doing these Migration Mania posts but I’m starting to feel the pressure of time running out: The Biggest Week in American Birding starts in ONLY 17 DAYS! There’s so much I want to share with you…our weekend birding Savannah, Georgia,….the birds we’re seeing here in Michigan now…what I’m looking forward to seeing in Ohio next month….spring is crazy busy!!

Visitor Guide for 2013 Biggest Week in American Birding
Visitor Guide for 2013 Biggest Week in American Birding

So in case I forget something, here’s a direct link to the online version of the Visitor Guide for this year’s Biggest Week in American Birding (click the image to the left to go to the guide). You can page through and read all about it. There are tips for beginning birders, articles about some of this year’s speakers, and lots more. I’m not ashamed to brag about being featured in it either — check out page 33!