Last week, I wrote a post about some bad science communication around bison and bobolinks. Later, I remembered I’d written about bobolinks for another project that never came together, so I thought I’d repurpose the essay here. Try not to think of it as leftovers – think of it as a response to your requests for more natural history information when you took the blog survey! Yeah, that’s what it is!
Birds that nest in grasslands tend to rely upon a ‘needle-in-a-haystack’ approach for success. Most build a simple nest, either on the ground, or suspended not far from the ground in a clump of grass or wildflowers. They then rely upon the camouflage of both their nests and themselves to escape predation by a range of animals or the sneaky brood parasitism of brown-headed cowbirds hoping to dump their own eggs in someone else’s nest.
Bobolinks adhere to the first of those principles by building simple nests on or near the ground. The females are also well-camouflaged; brown and stripy, which blends perfectly with the leaves and stems of last year’s prairie plants. Male bobolinks, however, are among the most flamboyant of grassland nesting birds, both in appearance and behavior. They’re no bird of paradise, but they are spectacular in their own right.
Every spring, I look forward to hearing the first bobolinks show up in lowland prairies in Nebraska’s Platte River valley, as well as other similar habitats. Their arrival is impossible to miss. The relative quiet of winter prairies is broken by the long, rambling song of R2D2 from Star Wars. Or at least a reasonable facsimile. If you’ve never heard the song, I promise it’s worth your time to look it up online.
That song is delivered by a smallish black and white bird as it flies through the air or perches prominently on one of last year’s wildflower stems. If I walk closer, the bobolink will usually circle around me, incessantly repeating its jumble of computerish beeps, chirps, and whistles, and giving me an even better look at it. For first time viewers of bobolinks, one of the slightly disturbing features of males is that the pale buff patch on the back of its head almost makes it look like the rear portion of the skull (or brain) is exposed. That buff-colored patch also seems to me to clash a little with the otherwise stark black and white feathers elsewhere – though no one should ever take fashion advice from me.
Like most other grassland birds, bobolink males establish and defend clear territories in the prairie. To clarify, the territory boundaries are clear to them, though not necessarily immediately obvious to us. If you flush a bobolink several times, though, and watch where it lands and where it doesn’t, you can get a pretty good idea of where its domain lies. You can also figure it out by waiting until a female bobolink emerges from the vegetation and flies into the air.
As soon as a female bobolink pops out, any male in the vicinity is right on her tail, chasing her like fighter pilots in a dog fight. I usually see at least two males join the chase, but sometimes a third one enters the fray too. Territory boundaries don’t prevent those males from following that female wherever she goes, but, at least in my experience, once she lands, only the male who owns the territory of her chosen landing place is entitled to land with her. The interlopers fly back to their respective territories and wait for another opportunity. There, they fly from perch to perch around the edges of their area of control, singing as if pausing to take a breath might give someone else the brief opportunity they need to interrupt. I love them so much.
The Prairie Ecologist 