M.A.P.S. / Studying a Captured Bird

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.

Common Yellowthroat

Inspecting the feet

Measuring the wing of a cat bird

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

M.A.P.S. / Checking the Nets / Extracting the Birds

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

Forensic Conjecture

At long last arrives a day warm enough for out-sitting and for drawing inspiration from its largess. So generous has this day been with birdsong, it would be hard to choose the music of only one species about which to write. Instead, with gratitude, I pause long enough to notice the variety, the buoyancy, and the understated exhilaration of the birdsong of early spring---whether it stems from the joy of first warm days or the sexual excitement that comes with the arrival of mating season.

Before I can begin again to reflect on the ever new noticings that reward my return to the backyard, I must tie up an unfinished blog topic described on November 7 & 13, just prior to my long absence---that of the mystery of the half-bird carcass.

My daughter, Hannah, shared the mystery with one of her graduate school professors who is an ornithologist in the field of environmental education. After some Q&A e-mails, Dr. Lisa Zinn conjectured the carcass to be that of an unhealthy tufted titmouse, and I learned more from her two e-mails than from a week of observing and wondering about the unfortunate bird.

I learned, for instance, that birds re-grow all their feathers every year; that asymmetry in bird feathers indicates a mutation, or illness, or injury; and that a stray white feather and white legs both indicate loss of pigment and lack of good health.

Dr. Zinn's response takes the educational value of this blog up a notch, that's for sure. AND, excitement of excitements for an amateur birder, she has invited me to participate in a bird-banding at the time of Hannah's graduation. Wahoo!

She has also graciously granted permission for me to post her e-mails in this blog. Below is a cut-and-paste of our e-mail exchange via Hannah. I reversed the order so you don't have to scroll to the bottom to read backward. Start at the top and read down in correct sequence:

HANNAH:
hey mom--i read your blog and sent the part about your half a bird to lisa my birding professor and thought she would know but she has a million more questions. :) this is her response:

DR. ZINN:
I read your mom's blog and I don't know right off what the bird was. I need a little more info. The most important being size. I am confused by her first thinking it was a mocking bird and than a Tufted titmouse because they are very different in size. Can you find out how big it was? Also, how white were the legs? Could they have been considered light blue? How yellow was the beak? Was it yellow on the top and bottom? She said it had a yellowish breast, how yellow was that? Was it just off white or distinctly yellow? Also, was the white outer tail feather really just one feather or several feathers? Heh! I guess that is a lot of questions. If you could just find out about the size and the legs (and maybe the beak) that would help.

DEB:
Fun---and all good questions. It was an interesting muse for blog, but I would hate for Lisa to spend a great deal of time on it. Only if she can ID from the description, with no extra research. Not that important!

Size: I almost addressed in the blog the absurdity of not being able to distinguish between titmouse & mockingbird, for the very reason Lisa suggests---the disparity in size---but didn't want to go on too long. I really couldn't tell what size it was, however, because only the lower belly and legs, lower back and tail were left--- a partial lower curve of the body. The soft under-feathers on the belly and on the back under the wings were fluffed, which might have made it look larger than it was. We first thought the tail looked long, but later decided it was an optical illusion----partly because we were so close, and partly because the tail made up most of what was left. To put a measurement on it , I'd estimate it to be about four inches from where it originated to tip.

Tail: It was a definite V shape (even more defined than that of a titmouse), not rounded, or pointed (as in mockingbird) --- the white feather(s) was only on one side, making it asymmetrical in color, which I did not understand. It was not the outer feather, but maybe the second or third one in----closer to far left side than center, and the feathers on the right side of center were all gray. (maybe it was a politically liberal bird :-) All I could see was the left edge of the white feather, as the tail was not spread. It looked like a white stripe that ran the length of the tail and was about 1/4 inch wide, slightly narrower at the top, and widening toward the tip. It could have been more than one, but looked singular to me. As I type this, it makes me wonder about a Carolina Chickadee, but that, too, seems too small for this carcass. Soft back feathers at point of tail's origin were a pale gray.

Yellowish underbelly: These feathers were fluffy and almost exactly the color of the belly or sides of a tufted titmouse, sort of a pale yellowish peachy color---or maybe a warbler of some variety?

Legs: White---Possibly could be interpreted as light gray or blue, with buff or tannish colored feet. Legs and feet seemed too long for titmouse, but wondered if it was because they were thrust out in an unnatural position. Feet were definitely more tan than gray, and darker in shade than the legs.

Beak: Was wide open and I could only see the interior----like two triangles edged in yellow, black interior, but probably due to decay----about 1/2 inch sides of the triangles---the tip was a little wider than 45 degree angle, not quite 90 degrees. Seemed shorter and wider than I would have expected---more like a nestling's beak. But I've never actually observed the inside of an adult's open beak :-) Also, too late in year for nestling. I was too squeamish to look directly at it for long---and though I wanted to flip it with a stick, couldn't bring myself to touch it even indirectly. The flesh that was left on the head was too messy to describe and gives me the heebie jeebies to recall it! (had to scrunch my face to type this)

A good puzzle for a Sunday afternoon. Love, Ma

DR.ZINN:
Ok, this is some interesting information. I will respond point by point.

Size: I completely understand how different bird sizes look up close as opposed to at a distance. There is definitely an optical illusion that happens with bird sizes. However, the 4 inch tail length is a very good clue and is about titmouse size.

Tail: The forked tail can also be a bit deceiving. Almost any bird tail can looked forked if you move the feathers apart for each other a bit in the middle. We have had trouble with this in bird banding because there are a few species where you have to look for a forked tail but it is pretty hard to tell when you are up close if it is genuinely forked because you can make it looked forked or not forked depending on how you move the feathers around. It is good to know, though, that the tail wasn't pointed and the tail feather's were not rounded. The information on the white tail feather was very interesting. The fact that it was not symmetrical changes everything! This is most likely not the color that feather was supposed to be but rather a mutation. Birds re-grow all their feathers every year and it is not unheard of for a bird in poor health to grow a white feather instead of the appropriate color. Birds also re-grow lost tail feathers so it could have lost that feather due to injury and the one that re-grew was white.

Legs: The fact that the feet were also darker than the legs makes me further suspect that this was not a healthy bird. It sounds to me like it was under a lot of stress and was unable to produce the required pigments for it's legs and it's feather. Either that or it had a mutation from birth that caused it to lack some pigment.

Summary: My best guess is that this was a rather unhealthy tufted titmouse that showed clear signs of stress. Perhaps that cat put it out of it's misery :)

Thank you, Dr. Zinn!
dkm