Our project to monitor Millerbirds is still underway, and it has been a busy two weeks since we got back to Laysan. These rare birds are no longer molting so they are making noise and, for the most part, cooperating and letting us collect the data we need given our limited time left on-island.
We are happy to say that we finally have a population estimate to share: about 160 Millerbirds on Laysan, more than three times the number that was originally translocated from Nihoa in 2011 and 2012!
As mentioned in prior posts, a lot of our work on Millerbirds entails re-sighting color-banded birds. Birds are marked with a unique set of color bands on their legs so we can follow individuals and get a better idea of their breeding history, movements, and population demographics.
Re-sighting birds is not an easy task with any species, but because of Millerbirds' secretive nature and the dense, bushy habitat they frequent, it is particularly difficult on Laysan.
After being evacuated due to the threat of a hurricane, I welcomed getting back to the familiar chase over the past weeks. Most mornings involve waking up before dawn and arriving in the core Millerbird habitat area (aka NIMI Land) in the northern part of the island just after sunrise.
These days the birds are particularly vocal, but there are still the sassy individuals who make you work to earn a re-sight. For instance, more often than not, I'll carefully navigate to a shrub where I heard a single chip note, only to arrive to silence: no rustling in the undergrowth, no fluttering just out of sight, nothing.
Moving ever so slightly to gain another view into the undergrowth, I look to the left, then to the right, and finally I see it in a small opening no bigger than my thumb. I see the small but wide-eyed look of a Millerbird that knows it has been caught.
It has not really been “caught,” of course. Until we get a clear look at its legs to see if it is banded and if so, what color-band combination it has, we do not know which individual it is and can determine little about its history and status.
It is at this point, especially with the really elusive sneaky ones, that I gingerly lie down on my stomach to try to get an eye-level view into the undergrowth where Millerbirds usually hang out.
The underbrush is a completely different world. A Red-tailed Tropicbird will chortle lightly, letting me know that if I come any closer, it will let out a shriek so intense I might end up with a temporary heart murmur.
The vegetation is thick, and choosing where to place your face for the optimal view can be a difficult decision. Once a place is selected, changing positions is costly, noisy, and just physically difficult with your face wedged between shrubby branches and your body bent and woven into other branches to minimize breaking any.
Deciding on a place is important, but this is only the beginning. A couple of seconds can feel like several minutes. My skin starts to crawl as the flies settle onto every uncovered piece of skin, licking up sweat or clustering on an earlier gift an overflying booby left on my shoulder. (Yes, feces!)
I start to time my breathing so as not to inhale any flies and also to blow off any that land on the tip of my nose… it has been all of 20 seconds. And then I hear it, a rustle just to the right, coming closer. I hear light hopping sounds… Millerbird? Rustling can be an indicator of a nearby Millerbird, but it can also be skinks, finches, or crabs.
Trying not to flush it the wrong direction, I hold my breath, making sure to only blink one eye at a time. Something in the periphery darts behind a broad naupaka leaf. Definitely a bird. It is still for a moment and my inner monologue starts chanting, “Come on, just a little leg, come on …” making me feel just a little bit like a pervert, but it is for science.
Then a leg slips out from the edge of the leaf. The black, stalky leg of a Laysan Finch. Not what I am looking for.
I would curse, except why waste a curse when the only one to hear it is a juvenile Red-tailed Tropicbird, and maybe a shearwater I haven't noticed yet? Hesitating for just a second, I settle back in, keeping tabs on the foraging finch nearby. The sound of the finch moving to my left could not be louder.
And then a chip note, and before I can even process where it comes from, a bird flutters into view not more than a foot away from my nose: Millerbird, an unbanded Millerbird. Then only a moment later I hear, just farther back from the Millerbird in view, a male singing lightly.
He comes into view, briefly displaying his color bands nicely while the unbanded bird starts fluttering its wings and “churring,” a good sign that the unbanded bird is a female and the two birds are a pair.
I note this and watch the Millerbirds for a second longer, and then they are gone–out of sight like it never happened, even though that finch is still foraging noisily nearby like Garfield chowing down on a pan of lasagna. I repeat the male's color combination obsessively over in my head, like a mantra, until I can write it down in my notebook.
These efforts do not all end in a double re-sight or even a single re-sight, but when they do, it is well worth the chase and the adrenaline rush afterwards.
Editor's Note: This story was originally published on October 20, 2014.
Barbara Heindl is a field biologist on Laysan Island monitoring translocated Nihoa Millerbirds. She has also done extensive work on Kaua‘i, Alaska, and across the United States' mainland. She is originally from Wisconsin and a graduate of University of Wisconsin-Madison.