Bird ringing: Guest post by Chris Laning
Bird ringing is nothing like bell ringing: it’s what in the USA we call bird banding. Banding birds provides an inexpensive way of tracking large numbers of individual birds, especially those that migrate long distance. A small, lightweight aluminum band is clamped around one leg of the bird: it’s stamped with a serial number and an address. Anyone who finds a dead bird with a band is encouraged to report it to the address given, with a note of when and where it was found. Because so many millions of birds have been banded, this actually yields a fair amount of data about where various birds go. As a college student and a biology major, (mumble) years ago, I helped with various bird banding ventures.
The difficult part about banding birds, of course, is catching them alive. The most common tool I saw being used was what’s called a “mist net” — ten feet or so of nylon netting, rather like a tennis net, but several feet tall and made out of extremely fine black nylon thread. It has stronger threads running horizontally at intervals, but when it’s stretched out between two trees, it’s practically invisible (hence the name). Birds fly into it and become entangled by their feet or feathers.
Mist nets need to be checked every hour during daylight without fail, so that any birds caught aren’t in it long enough to become dehydrated. Bird banding means you are responsible for the lives of the birds you are studying, which is why you have to be licensed by the US Fish and Wildlife Service (or the equivalent in other countries) to do it — otherwise catching or trapping wild non-game birds is illegal in most countries. There are inevitably a few casualties, but no bander wants to see birds die, so the ones I’ve worked with are extremely careful how they handle their nets and birds.
Most birds when caught in the net will just lie there quietly once they figure out they can’t get loose. A few are fighters; I was making the rounds with a bander I was helping when we heard a commotion in the next net; we ran up and there was a small hawk caught and dangling by its feet, struggling to get loose.* That’s rare — a bird that big can usually tear the net and free itself. Smaller birds just get more tangled the more they try to get loose. We caught a lot of warblers, finches, sparrows, thrushes and other small and medium-sized birds.
Our human fingers and opposable thumbs make it fairly easy to free most birds from the net. We used to carry a pair of nail scissors to snip threads if something got really badly tangled. (Better to have to mend a net than to have something die.) As we made the rounds, we’d carry a supply of small cloth drawstring bags, and when we removed a bird from the net, each one went into its own little bag, where it would usually quiet down again. We’d come back to camp like Mighty Hunters with a row of bags hanging from our belts, perhaps a dozen or two birds from six or eight nets, unless it was the middle of a heavy migration season when it might be more.
Wild birds don’t like being handled. Being held means something has caught you and is going to eat you for lunch. Birds also have to be handled very gently because broken feathers impair their ability to fly or to keep warm, and thus to survive. For a small bird, the best way to hold it is to put your hand over its back so that the head sticks out between your index and middle fingers and the rest of your hand closes gently around the body and wings. Knowing this came in handy for me once when a hummingbird got into the bathhouse at summer camp and kept trying to get out through the window screens — I was able to chase it into a corner, and then its bill got caught in the screen and I could close my hand over it and carry it outside.
Different birds have different manners. On one trip we decided that the real Bird of Peace is not the dove but the ovenbird (a quiet, ground-dwelling bird) because it would usually lie in our hands quite calmly. Doves tend to panic and flail around. Chickadees and finches are the real Birds of War and will peck your fingers mercilessly.
The banders I worked with were generally studying migration, especially warblers. Most birds would be banded, and then weighed (gently stuffed head down into a paper cone hanging from a small spring scale) and released. I was the record keeper; careful notes have to be kept of which bird was given which serial numbered band, when and where. These records get sent in to the Fish and Wildlife Service so that when a band is reported to them, they know where the bird has traveled from.
Warblers, the main object of the study, were not only weighed but had their age, sex** and general condition noted. The way of doing this was very clever. Warblers only live a few years, and like humans, the sutures or joints between the bones of their skulls gradually grow together as they age. You can tell first-year birds from adults if you have them in your hands by carefully wetting and parting the feathers on the tops of their heads (the birds look very silly with parts) and looking through the transparent skin of the part with a hand lens to see the bones. Similarly, to see how fat the bird is, you flip it over, blow gently to ruffle the feathers on the belly, and you can see fat deposits under the skin. The amount of fat got a simple numerical score from 0 to 3. Birds eat constantly and have to store up a lot of fat as fuel for their migration.
Then we let them go. Generally you simply turn your hand palm up so the bird is lying on its back, and when you open your fingers it will jump up and take off. Sometimes for fun we would put a bird to “sleep” — if you turn your hand palm up and gently swing your hand up and down a few times, it seems to lull the bird, and when you open your hand carefully it may just lie there quietly for several seconds before it “wakes up” and flies away.
I didn’t pursue a professional interest in birds much past my college days (I turned into a botanist and then a medieval historian) but I’ve always been glad for the experiences I had and the things I learned.
Birds are wonderful creatures, and to be able to see them close up and hold them in my hands for a few minutes was a rare privilege.
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*Five more minutes and it would have torn itself loose and flown off; it was sheer chance we happened by at the right moment. The bander did manage to untangle it and took it straight back to camp, leaving me to finish the round. By the time I got back she had weighed, measured and banded it and let it go, sustaining a not a few pecks and claw slashes in the process. She said it was a good thing she’d brought some larger- sized bands in the kit, since you never expect to catch something that big in a mist net.
**Sex of course you can generally tell by the plumage, unless the bird is very young, since adult males and females are colored differently.
In spring they are in “breeding plumage” which makes it easy; it’s harder in fall when they may have changed into duller winter plumage, but since you have them in your hands you can usually see enough details to tell what you’ve got.
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