Monday, May 2, 2016

Banding Parallax



Walking in circles all day. That's the basis of bird banding. We set up loops of trails in the forest, studded by ten 12m-long, extremely soft and nearly invisible nets (hence the name mist-net), and walk them every 40 minutes. The paths become apparent even after a few days, leaves and little saplings pressed into earth, soil compacted beneath. The banding trails at Point Reyes Bird Observatory in California, where I conducted my training, have been walked by interns for 30 years, and look more like canals than footpaths: deep, smooth earthen trenches dug by boots and rain out of the forest floor.

As birds are flying along, minding their own business, they might suddenly feel a peculiar but insurmountable horizontal gravity. The nets are made of thread, basically – loose mesh diamonds of black thread that flutter slightly in the breeze. When a bird flies into one, he or she sort of somersaults into a pocket of mesh and then, confused by this sudden change in trajectory and paralysis, struggles and gets itself tangled just enough to be unable to flap back out. Usually the head, if its small enough, and one or both “wrists” get looped and then it's stuck until we come along to liberate it. But it doesn't see us that way. It thinks we want to eat it, and so struggles some more in an attempt to save its own skin, usually making our job harder. It takes a lot of training to understand and practice the fastest, safest ways to extract tangled birds. After awhile it seems as easy as taking a cardigan off a small child. Every once in awhile, they are so tangled no amount of training can help you. Then you use scissors. I have yet to need scissors. I hope I never need to.


 Wattled Honeyeater in net

Different species react differently to being in the nets and being handled. Warblers and small hawks tend to go comatose – just sort of lying there, barely tangled – and extracting them is like picking a spoon out of the utensil drawer. Chickadees are tiny and ferocious, thrashing and spinning into anarchic balls of yarn, screwing their eyes shut with the effort. Most banders loathe trying to undo the chaos they cause. Woodpeckers use their tools against you, thwarting your efforts by drumming any inch of your flesh they can aim at with their pick-ax bills. I saw a master bander come back from the net with a Pileated Woodpecker muzzled by a Pringles can, his hands streaming with blood. His own blood; leaking from a hundred puncture wounds. Most of the time, its a swift procedure, a minute or less, plus another to take some measurements, jot some notes, and they are back on the wing.

As a banding technician in American Samoa, what strikes my heart with anxiety is finding a Samoan Starling in the net. They look very much like smallish crows: dark with large bills and calculating eyes. As soon as they see you approaching, they start screaming. Ear-splitting shrieks from the moment you arrive until the moment you let them go. And they are occasionally “tongued”, which is as bad as it sounds. Their tongue is shaped like an arrowhead, and they somehow get a few threads looped around the back points, then they grab a handful of net with their sharp talons and pull, sometimes until their tongue bleeds. And then as you try to undo them, they bite, jab, and stab at all your most vulnerable parts – in between thumb and forefinger, the wrinkles above your knuckles, the flesh alongside your nails, and especially wounds from previous starling encounters, over and over and over. And if they get a good grip, they thrash their heads from side to side like a prize bass, trying to rip the skin right off your fingers. It's as if they want to take vengeance for all the birds who have ever been banded, for all the inconvenience and confusion humans have enacted on all avian species in the name of conservation.

 Samoan Starling mugshot

Remember, they are also screaming this entire time, even with a mouthful of your flesh and a bleeding tongue. It's traumatizing for everyone involved. And every time, it makes me wonder. Why the hell am I doing this? Why are scientists harassing birds, interrupting their already stressful lives, just to give them an identification number in case we get the chance to harass them again? As an intern last fall, jarringly presented with the dichotomous nature of wildlife-handling, I asked this question again and again: asked my trainer, asked the scientific literature, asked my soul.

Maybe growing up in the suburbs, sheltered from lions and wolves and anacondas, surrounded by my cherished and ever-growing plush menagerie, led me to believe that animals are soft (many are, incredibly) and that touching animals was a way to connect with them. Raising pets teaches us that animals enjoy being scratched and patted and belly-rubbed. Children instigate formative emotional bonds with nature by snatching small snakes and lizards out of the grass and feeling them wriggle free from their grasp. Being human with hands that hold and caress and nurture, I instinctively want to use my uniquely nimble appendages to calm small creatures in their moments of terror, to hug them and tell them everything's going to be alright. But the truth is, as a scientist, I am causing those moments of terror. And the very last thing that will comfort them is being touched by me. To them, I am no different than any other predator that wants to rip them into bite-sized pieces. It's a heart-breaking realization, the power-balance so repulsively tipped that it wrenches any magic I anticipated out of such an intimate encounter. It makes me feel content to bridge the space between myself and wild animals only optically, through binoculars.

The main objectives of MAPS banding programs (Monitoring Avian Productivity and Survivorship) such as the one we are flagshipping on Ofu-Olosega, are thus: to provide annual estimates of adult population size and survivorship, proportion of resident individuals in a population, recruitment of hatch-year birds into the population (AKA survival of their first harrowing year), and population growth rate using mark-recapture data of adult birds. If that sounds like a lot of jargon to you, it basically translates to learning whether adults or juveniles are surviving, so researchers can further hypothesize about specific threats effecting the population. For example, if it seems like there are less Cerulean Warblers than there used to be, is it because something is causing massive nest failure or keeping young birds from surviving their first year, but the current generation of adults are doing fine? Or is there something more overarching that is killing off adults as well? Are they returning from their wintering grounds? Are nearby populations doing similarly or is the trend specific to this portion of habitat?

Long before the MAPS program was established, people were watching birds. And counting them. The Breeding Bird Survey and Christmas Bird Count exemplify programs that have been estimating bird populations for decades, and it would seem the information gleaned from this data would be sufficient to understand bird population trends over time. Because of them, for instance, we know for sure that aside from a few species that adapt well to human-created environments (if you're not a birder, these are the birds you probably see the most of: species that love cities and suburbs as much as we do), birds are on the decline across North America. The major threats to birds last century were over-hunting and specific toxins such as DDT leaching into the environment. Thanks to management strategies and wildlife refuges, hunting is less of a problem, at least in the US, and the EPA removed DDT from production. But the last 50 years added climate change, invasive species, and rapid habitat loss to the list. I've always hated that term – habitat loss – as if we simply couldn't find it, though we swear it was around here somewhere. Although, maybe that describes the phenomenon perfectly – a forest is cleared for a suburban development, a few old residents are devastated as they witness a drop off in biodiversity, and the new ones, growing up in the streets named for the trees they replaced, have no recollection of what they are missing.

Anyway, we know birds are declining. Not just the Passenger Pigeon, whose populations were so mythic in proportion we have all heard the stories yet have a hard time imagining it now – flocks streaming across the countryside so thick they blotted out the sun for hours. Now there are none. Older generations, who spent more time outdoors, will tell you they've noticed a lack – it just seems quieter out there these days. Counting birds lets us know that what the old timers say is true, but it doesn't provide the answers why. Setting up nets and catching individual birds, giving them nearly weightless identification bracelets, and sending them back into the wild, provides a deeper glimpse into their lives.

But it's still just a glimpse. Recapture rates are abysmally small – ranging from 1 to 30%, depending on the banding station. Some stations, especially breeding-focused MAPS stations, host a lot of resident, non-migratory birds that are recaptured many times a season. Others, such as fall migration stations, are located along migratory pathways and catch birds who come through once a year and might never return. Additionally, each station is only a few hundred square meters of reality – a tiny porthole into the vast tanker of nature. But tracking the individuals we do recapture tells us who is surviving, and who is returning to their breeding grounds. Sometimes banders even pull one feather or take a tiny drop of blood and send it to a lab for analysis. This is how researchers have tracked a wide variety of data from migration paths, to genetic variation informing changes in the taxonomic order, to the spread of introduced illnesses like West Nile Virus in some North American species, and Avian Malaria in Hawaii. It sounds invasive, but after decades of banding birds of all sizes, scientists know that the few minutes of confusion and stress that banding causes birds has minimal effect on their livelihoods.

Backyard banding was a hobby in the early 20th century, but now banding operations are strictly regulated and conducted only by trained and permitted researchers, always with the safety of the birds taking precedence over data. The injury and fatality rate is less than 1%. Accidents do happen, and I have witnessed both irreversible damage and the miraculous – I once recaptured a healthy adult bird with a slightly crooked leg, looked up his stats in the database, and found his leg had been broken during banding several years before, splinted and taped before he was released. It clearly healed and he has been doing fine ever since. Even the Samoan Starlings seem to fair well after having their tongues lacerated – their ferocity reflects their tenacity. And thinking about it, I suppose my tongue heals pretty quickly after biting it, too. Some individuals are recaptured over and over and over throughout their lives, and because of it, researchers know that the process has little effect on their livelihood and have even illuminated lifespan records for many species.

MAPS stations across the continent (and on Ofu-Olosega) also conduct habitat surveys in conjunction with banding to link population trends with changes in habitat quality. Birds cannot exist alone in the sky: they rely on evolutionarily specific environments in which to hide from predators, find food, and build nests. The data gathered by annual banding stations contributes to land management and conservation strategies, as well as evaluating the success of implemented strategies in real time. At least, that's what I've been told by my supervisors and the scientific literature. I have yet to witness a specific example, but I am still freshman in the school of bird banding.

All of this is what I try to tell myself when I find a Samoan Starling caught in a net by his tongue, and spend minutes drenched in sweat, struggling to free him while he pummels my hands with his knife-bill, screaming until I want to scream myself. All the feel-goodie conservation stuff gets flushed from my psyche when I suspect injury in the bird I am handling. When I suspect my good intentions have caused grave consequences for the very thing I am trying to “save”. It makes me sick to my stomach and declare this to be the last banding job I ever sign up for. It makes me think the whole thing is a farce, that biologists don't gain any vital information from all those numbers, that its just an excuse to hold a beautiful, wild creature in your hand while you take a selfie that you can post online when you get back to civilization. It makes me think science is too focused on the species at the expense of the individual. Even the terminology is suspect – birds are not just banded, they are “processed”, like a cut of meat in a factory. It starts to feel like modern conservation is relegated to deciding between the lesser of two evils: invasive intervention or environmental destruction. My erupting emotions make me want to drop out of banding academy altogether. I return to our field house in the afternoon with heavy heart and a knot in my stomach.

And then a few days later, we catch a Fruit Dove. A resplendent, shining piece of feathered rainbow, a male Purple-capped Fruit Dove lay docile in the net after a whole morning of empties. My heart fluttered with excitement as I carefully removed netting from his magenta-lidded face. His eyes were bright and clear and somehow reminiscent of dinosaurs resurrected in our collective memory by Jurassic Park. His underbelly pulsed with all the hues of the most vibrant sunset you've ever seen – fiery orange, lemon yellow, flamboyant fuchsia, moody burgundy – as refreshing as a sno-cone in the dog days of summer. His only expression of discomfort while I held him for banding were his toes clenched tightly around each other – like the hands of a worried little monk clasped beneath his cloaksleeves. He never struggled, never bit or clawed out, never uttered a peep. And he smelled so wondrously sweet like flowers, I wanted to bury my nose in his soft plumage forever. Then we sent this rainbow back into the sky where he belonged, his wing beats strong and thrumming with wild vitality.

And I realized: I am sucker for this banding stuff after all. Many young scientists, including myself, are at least partly drawn to banding birds by the fleeting moment you get to hold a vibrating piece of wilderness in your hand then send it on its way. And for many, even and especially veterans, the motivation to continue is fueled by the desire to understand and conserve. Science claims to liberate itself from human bias, but what human activity isn't at least motivated by our fickle emotions? Emotions that cascade into opinions and passions but also action, determination, discovery. If the data collected really can help ensure the abundance of these gorgeous, mysterious, even ferocious creatures into the future, then maybe it is worth a few moments of discomfort – the birds' and my own. Maybe. I'm still not sure. Anyway, I still have two more months of walking in circles to decide.



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