My Time with the Birds

I do not remember the first bird, but I do remember what happened to me as I watched him die. 

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My whole body cramped. My vision went blank. 

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I left the lab where my scientific mentor was demonstrating how to euthanize the bird and preserve his brain. I put my head between my knees and breathed deeply. 

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I went back into the lab but had to leave again, weak-kneed.

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When I returned the second time, the bird had been reduced to his brain. Brains, I knew. My body re-equilibrated as I observed the rest of the protocol, but my recovery was slow, possibly still unfinished four years later.

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Songbirds are a research model that allow us to study the neural bases of language. Like humans, songbirds communicate vocally and learn by listening. Just as human babies babble as they learn to speak, imitating sounds they hear, some songbirds, including male zebra finches, go through a phase of "proto-song" where they imitate pieces of an adult tutor’s song. At about 90 days of age, the proto-song crystallizes into a full adult song, similar, but not identical, to their tutor’s. 

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They sing only this one song their entire adult lives, so this learning process can be closely tracked in a lab, such as the one I worked in as an undergraduate. Behavioral tracking can be coupled with cellular biology techniques to help us learn what happens in the brain on the level of individual neurons during the process of vocal learning, making zebra finches a popular model among neuroscientists like myself.

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In addition to being a unique model of learning, zebra finches are also an excellent model for studying neurogenesis, or the birth of new neurons. Unlike most mammals, they are not born with most of the neurons they will ever have. Only a few human brain regions, including ones involved in learning and memory, neurogenesis long after development. This association between neurogenesis and areas involved in high brain functions raises many questions – do the new neurons contribute to the learning process differently from the other neurons in the same area? If so, how? While it is difficult answer these questions in humans, neurogenesis can be accurately traced in zebra finches in analogous brain areas.

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When I saw my first bird die, I had read extensively about this science. I was sold on the importance of songbird models in discovering the basic neural principles of human learning. Sacrificing animals was a vital, if unsavory, part of basic science. I was reconciled and I was ready. I did not expect my visceral reaction to the death, my body reacting differently than my logical mind. Part of me felt pride – what a deeply human reaction I'd just had, and at least I was able to feel a death inside the bounds of scientific method. Part of me was embarrassed – could I be a serious scientist if I did feel deaths this way? I felt like an anomaly in the lineage of women scientists who I admired, who despite being told they couldn't, did. Could I?

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There was no choice but to adapt. I practiced killing birds who could not be used in experiments, beginning by deeply anesthetizing the bird and ending by carefully lifting the brain out of the skull. The actual moment of death passed quietly near the beginning. As it got easier technically, it got proportionally easier emotionally, but I never quite mastered it. Despite the practice, I sometimes still felt a twinge of something beyond the routine. 

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Once I was confident enough, I began my own experiment. I exposed birds to a familiar song, an unfamiliar song, or no song prior to killing them, preserving a snapshot of their brain activity during this song or silence so I could investigate the role of neurogenesis during this auditory learning. To ensure that most of the activity was attributable to hearing (or not hearing) the song, I did this early in the morning, when the birds were unlikely to be active and singing.

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This became my lonely, quiet morning ritual – trek across the sleeping campus to orchestrate the last sounds of birds' lives. I let this quiet monotony scab over in me. I could not sustain the bodily reaction I had had to the first bird. I did not want to lose the tenderness of the birds and their deaths, but I needed it covered because a constant open wound would keep me from finishing the job. After starting, I owed it to myself, the birds, my lab, to follow through.

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As spring came, I killed my final bird and collected my final brain. I moved from quiet mornings in the lab to quiet afternoons in the basement microscope room, adjusting the focus so the cells lit up and revealed their secrets. As I gathered my results and wrote my senior thesis, I embarked on a parallel project. With a beloved professor and group of compassionate peers as guides, I wrote pages and pages of poetry and prose reflections, carefully removing scabs to let my confused emotions breathe. I sought a non-procedural, non-numeric relationship with the birds. Carefully, I took my memories of those mornings when I covered up my feelings and added feeling back in – added the birds, now as living entities rather than test subjects, back in. This uncovering was a different type of ritual, to exorcise the dark, numb mornings so I didn't need to carry them, in all their unfeeling pragmatism, in my memory. I was careful to titrate this exposure, because experiencing the full reality of the lives I had taken all at once could send me back to that shaking, light-headed place. That would not be a healthy way to live my own life or to honor the birds. Completing my science and learning that my experiment supported my hypothesis of increased flexibility in adult-born neurons was one form of honoring, but this felt incomplete. Spending time reflecting on the birds as their own entities, I sought to know the birds as I knew their brains – only in symbols, tags I carefully constructed to illuminate some meaning. My completed project, a book about the size of a bird, provides an alternative to living unstably with overwhelming emotions. Now I can carry in my hand a reminder of my relationships with my birds.

 

I have moved away from animal research as a graduate student, exchanging the quiet control of the aviary, where I could manufacture song and silence, for the hubbub of a clinical environment. But I have not left the birds behind. Intellectually, very little changed for me during my time with the birds, and I still see great value in animal research. I know that my work laid the foundation for future experiments in the lab, inching us closer to understanding the mysteries of the brain. I cannot, however, fully intellectualize my time with the birds. Each animal researcher I know finds their own closeness to and distance from their subjects. For all my distance – temporal and scientific – from my birds, their brains and their songs, their lives and their deaths, will always be nearby.