Thursday, April 26, 2012

My boyfriend might be a girl

I have a confession.

I am in love with White-Throated Sparrows.

What is not to love? They arrive in the spring, just when you are starting to get tired of mud and snow and the delicate brownish grey color that everything turns when it's dormant. Suddenly, these cheerful sparrows arrive (well, I don't know if they are cheerful. They're probably just hungry. I'm cheerful, though) and are singing delightful songs and wiggling their glorious yellow eyebrows (lores) at me. Oh, be still my heart.

They congregate in small flocks in late April and May, singing and singing, kicking through the underbrush for food, and milling around under my black oil sunflower seed feeders. Their ground locomotion is hopping, and the ones here are not shy about coming nearby as long as I am still and peaceful (more like oogling those crazy amazing eyebrows).

A particularly bright Tan-Striped
For a long time, when I had older birding books and guides, I thought I was seeing both immature, adult, male, and female White-Throated sparrows. I took delight in being able to tell them apart and continued to swoon over the ones with the brightest markings, and the most lovely yellow lores. I jokingly called them "My Boyfriends," which probably isn't fair. It's only a boyfriend if it's mutual, is it not? And certainally, the sparrows were not overly interested in me beyond "Hey it's the seed lady". So perhaps my 'secret crush' is more appropriate. It's true. I stalked the sparrows, like a creeper. I watched them eat and preen. My word!

You can imagine how my world came crashing down around my knees when I discovered that White-Throated sparrows are not sexually dimorphic. This means that the males and females are not visually different. My boyfriends might have been girls! This was getting complicated.

To add to the complication is the fascinating fact that White-Throated Sparrows actually have two genetically-linked color morphs. They are polymorphs! Some sparrows are the bright, boldly marked individuals that we are more familiar with; bright white stripes on the crown, dazzlingly handsome lemon yellow lores (eyebrows), and a more defined grey breast with a white bib. Those boldly marked sparrows are often referred to as the 'White-Striped" morph. On the flip side, there are the more drab (and female or immature looking) sparrows, that have far less defined markings on the breast, the crown stripes are tan, the lores are a desaturated yellow ochre, and overall they are more tan in appearance. These are, appropriately, referred to as the "Tan-Striped" morph.

Very curiously, in my observations the white-striped individuals seem to be far more bold... coming nearly to my feet when I am sitting outside. They are brash, and more quick to ire with other sparrows, chasing them and chattering angrily. The tan-striped birds are much more mellow, peaceful, and a bit more shy at times. This was one reason I truly thought that the brightly colored white-stripes were mature males, while the others were dour females or adolescents. Wrong! I did some reading and apparently this is such an interesting phenomenon that many scientific studies have been made on these finches, their society, and the color morphs. It seems that females of both colors prefer the more mellow and faithful white-stripes, whereas the males of both colors prefer the brightly colored white-stripes. Augh, my head is spinning! This sounds like a crazy sitcom, but it gets even better. Because the aggressive white-striped females are more pushy, they get their pick of the tan-striped guys, so the more meek tan-striped girls are more likely to choose a white-striped male because all the good guys are taken. White-striped males are boisterous and randy apparently, and are not very faithful to their preferred white-striped girls... so when hubby is away, sometimes a tan-striped male will come in and mate with the white-striped female. True stuff! Did I give you a headache yet? And you thought our society was bad when it came to relationships.
Typical Tan-Striped

All of that means that there is approximately the same number of white-striped and tan-striped offspring each year. All because my boyfriends are complicated birds, indeed.

Somehow though all of this, my husband likes me for some reason, and announces with a laugh that my non-"boyfriends" are in the yard. Still, I am not ready to renounce my love for these way cool little birds. I just have to admit to myself that love is complicated.

I've taken two short videos; one of a white-striped sparrow and one of a tan-striped sparrow, if you want to see them in action.

And a lovely video, not my own, of their wonderful song.

1 comment:

  1. Oh wow, how interesting! And this is something observed by other people, too. I wonder if any scientists have studied the jays and their hawk trolling? I think that's at least as interesting as the white striped/tan morph society.