Wednesday, June 30, 2010
To hold a wild bird in one's hand is to touch the pulse of the natural world. The warmth of its bird body, the beat of its heart, the clutch of its foot around a finger, the quiver of wing. Each sensation, taken individually, was a thing of wonder; collectively, they coalesced into an awareness like no other, of such combination of frailty and bravery and stoicism and toughness and patience and endurance and perseverance and grace as to be a model for how we all should live.
Yet such sentient abundance paled next to the exhilarating release of tension that came from the lifting up and letting go of each bird---to feel it take leave, to see it first dip then rise into the air on its own power when only seconds before it had been powerless against the soft fold of a human hand. The high competence of a small bird in the face of what must have been a terrifying ordeal was exemplary. Unrolling my fingers to return each bird to its own wild brought a lightness of spirit to be remembered for a lifetime. dkm
Tuesday, June 29, 2010
If a bird captured for momentary study does not already sport a numbered leg band, one is applied. Banding is the final step in the process, after examining the bird, after recording the collected data, and before the ultimate release. I could never have guessed how one goes about putting a metal band (I think it is lightweight aluminum---please correct me if wrong, Dr Zinn :-) around a wild bird's leg without hurting it, so again my curiosity was piqued.
Of course, as for most human endeavors, there are tools perfectly engineered for the task. The thickness of a bird's leg is first measured with a simple but cleverly designed instrument of calibrated notches, in order to select the correct size of band. The sizing instrument is a flat plastic card with notches along all four sides that correlate with all potential leg sizes. This photo shows the leg-sizing card, the apparatus for measuring the wing, and the hand pliers used to clamp on the band.
The bands are small metal tubes, open on one side like the letter "C," that come on a carefully regulated wire, so as to always be applied in proper numerical order. The precisely sized and numbered band is inserted into a specialty pliers, again with perfectly sized notches engineered so as not to injure the bird, and using the hand pliers, BINGO,the band is gently clamped around the shaft of the leg, allowing it to fit like a loose bracelet.
Swallow, little swallow, (a reference to Oscar Wilde's The Happy Prince), your discomfort is almost over. Next step, release, but for that near-religious experience, you must wait till next post. dkm
Monday, June 21, 2010
Most surprising of all the new information gained on my bird banding day was how gender and reproductive status are determined in species that look alike. The researcher blows on the belly to part the feathers, thus revealing either a female's "brood patch" or a male's "cloacal protruberance," both of which are red and swollen during the breeding season. The brood patch is a large featherless patch on the breast and belly with which the female warms her eggs or nestlings. The cloacal protruberance of the male is what it sounds like.
I found it comical to discover that the brood patch is assessed with descriptive terms like vascular, wrinkled, smooth, heavy, and molting, while the cloacal protruberance is assessed only for small, medium, and large. Make of that what you will regarding cross-species similarities, but don't deny that it makes you laugh.
Determining flight feather wear
Blowing apart the feathers to assess "brood patch" or "cloacal protruberance"
Recording the data
The data collection was fascinating to watch. Each bird was inspected, measured, and assessed at close range for more than 30 specific bits of information, all of which were meticulously recorded, and many of which I had never before considered. My learning curve was high. Things like flight feather wear, molt limits, plumage; measurements of wing, skull, tail, body fat, eye color, mouth & bill, and much much more, for the purpose of determining age, gender, health, and reproductive status. Much of it was more technical than I was able to follow, though I found it intensely interesting---especially the myriad determinations about the plumage---the primary & secondary coverts (outer feathers), and inspecting the molt limits for primaries, secondaries, tertials, and rectrices to determine age, history, and health status.
If the captured bird already had a band on its leg, the number was recorded along with the new data, later to be entered into computer and compared with earlier observations of same bird. If not, it was given a band, a process to be described in next post. dkm
Sunday, June 13, 2010
Step two of the bird banding day was to check the nets and extract any captured birds, which we would do every half-hour throughout the morning. It is still darkish in northern Indiana at 6:30, but now the birds are singing like crazy, unlike the quiet of 6:00 when we opened the nets. To my untrained ear it is a random dawn chorus---beautiful but indecipherable. To Dr. Zinn, it is an audible map and promise of which birds might be caught, banded, measured, studied, and released on this day. I am nothing less than astounded at the numbers of individual bird songs she can hear, identify, and imitate, including her fluency of mnemonic codes for each.
I meet the gathered team of five expert bird banders---Dr. Zinn in the middle, three graduate students including my daughter Hannah, and a gentleman volunteer who is a retired biologist from Cornell ornithology laboratories. I notice they are all wearing waterproof boots. Already my wet cold feet tell me why. Promptly at 6:30 the team members clip a few small drawstring bags to their belts, get their net assignments and head out. The bags, made of white cloth, are for carrying the birds, once extracted from the nets, back to the banding table. They prevent trauma, injury, and escape.
I follow Hannah to our assigned nets. My shoes and socks soak up the morning dew as we slog through the long prairie grass. Of our three nets, two are empty, and one holds two small brown birds struggling to get free---a song sparrow and a female indigo bunting. An indigo bunting! Hannah gently cups the first thrashing sparrow in her hand, holding its neck between two fingers so the head is on the outside of her hand, the body in her palm. She carefully lifts each thread of the net from the body, but the feet are so hopelessly entwined as to necessitate calling Dr. Zinn for assistance. The second, the bunting, Hannah extracts easily and drops into a bag. Dr. Zinn arrives from somewhere in the dawn to skillfully rescue the sparrow. We carry them back to the banding table. I imagine myself to be a small sparrow, stunned by whatever I have flown into, frightened by the monster hands, mystified by the whiteness from which I cannot escape, unable to understand that this is a temporary discomfort or that I am making a contribution to scientific research. I might be fighting for my life, but I'm not sure, because so far I'm not hurt and no one is eating me. Who knows? I only know I don't like it.
I, as an amateur observer of the work, am thoroughly energized by the experience---the wonder of the natural world, the thrill of new knowledge gained, the marvel at the organizational efficiency of the bird banding process, the care and respect the researchers exhibit for each tiny specimen they study. More on that part of it tomorrow. dkm
Wednesday, June 9, 2010
I had the remarkable opportunity to participate in a bird banding last week, thanks to my daughter and her environmental education professor, Dr. Lisa Zinn, whom I have consulted in earlier posts on questions about backyard birding. Dr. Zinn organizes bird bandings for MAPS (Monitoring Avian Productivity & Survival).
I was honored by the invitation and had no idea what to expect of a bird banding. Will describe it in detail, assuming anyone interested enough to be reading this may be as curious as I was about the details of banding birds. It will take several entries to describe.
Opening the Nets:
Our day began at 4:30a in order to arrive at the banding station in time for the 6:00a spreading of the nets. The only recommended attire was water proof boots, which I did not have, but after the first 30 minutes, wished to.
By the experts' casual references to opening the nets, I'm sure they would be surprised at my intense wondering about what exactly that meant. What it meant was untwisting a large black rectangular-shaped net and stretching it vertically between two 8 ft tall poles, about ten yards apart. When the net was fully untwisted, spread, and hooked up, it made an invisible wall between the poles, 8 feet high by ten yards wide. The nylon strings of the net were as fine as sewing thread but unbreakable, in a grid of half-inch squares. The net itself was three layers thick, the top of each layer lower than the one behind it so that no matter where a bird flew into the net it would fall down into a pocket made by the next lower layer, and thus would be held captive in the net without getting hurt.
Ten such nets were set up at strategic locations around the marsh and grasslands of this nature preserve in northern Indiana. Once all ten nets were spread we sat down at the banding station with a good cup of coffee to wait. In a half-hour, and every half-hour throughout the day, we would check the nets for captured birds. That's enough for one day's entry. More tomorrow. dkm