Jan 21--Mist Netting

Saturday, January 21, 2006
La Mono

Up at 5:00 for what has become our usual routine: Breakfast under the casita in the dark, illuminated only by candlelight and our headlamps. Out at 6 am to open the mist nets, each team to its own nets. Cathy and Jessica and I have our route and routine down and slog across the creek, climb the bank—which has become so deeply muddy that we have had to cut another trail around the original one—hike to the mist nets, unfurl the mist nets and stretch them out on the poles one at a time.

Mist nets are nearly invisible nylon mesh nets about 40 feet long and 8 feet high, strung between a couple of bamboo poles. The size of the mesh varies, depending on what kinds of birds you're trying to catch. For hummingbirds, the standard mesh is 24mm; for "average" birds, 36mm, and if you were primarily after large parrots or toucans, your net would have even larger holes. The largest bird we caught in the nets I think was a Collared Trogon (right), a pretty solid bird about 10 inches long.

Collared Trogan

The nets have 5 trammel lines stretched tightly between supporting poles, but the net between those lines is not stretched tightly at all. Almost any bird that flies into the loose, nearly invisible, net becomes entangled. The nets are black gossamer. Anything that touches them—including our clothing, sticks, leaves, insects—catches or gets tangled in the netting. We often have to free cicadas. Cicadas are everywhere in the Cloud Forest and louder than those in Oklahoma . . . if that can be believed. When they all set up a racket, it actually hurts the ears and we put our hands over our ears. But, these cicadas are a beautiful turquoise pattern and exceedingly  pretty. In fact, not realizing the numbers we would find at camp, I carried one carcass all the way up to the camp so that I could photograph it (definitely coals to Newcastle). We even got photos of one hatching out on a nearby tree (see below).

A gorgeous turquoise cicada hatching and getting its color

It is still dark when, after opening the nets, we return to the banding table and another cup of coffee while we wait the requisite 20 minutes before hiking back to the nets to untangle and bag caught  birds.We mist net for 5 hours each morning. Each day we net fewer birds as the birds become aware of the nets. This morning we band about 82 birds, 28 of them hummingbirds.

Evelyng holding a bird at the banding table; note the sheet for data bottom left

We have an hour of downtime after lunch, during which time a few of us play scrabble or rummy. After this, Susan and a group hike back up to the hummingbird pasture to monitor the feeders. Marlene and I stay down and sit under the casita to enter into the computer all of the data collected in the morning. It takes Marlene and me all afternoon to enter all these data on the birds we’ve captured this morning. We are proud when we enter the last item. Susan is very pleased.

Alejandro with one of the banded hummingbirds that is regainig its strength before flying away

Post-lunch downtime; me, Chas, and Dawn

Here are the data collected for each bird:  Date, Weather, Time, Bander, Site, Species, Band Size, Band Number, Age,  Age How (plumage, skull, primary feather wear), Sex, Sex  How (plumage, brood patch, cloaca, rectrix shape), CP (Cloaca Pr.) ( 0  = pres. but not enlarged, 1= slightly enlarged, 2 = large, diameter as large near tip as base, 3 = very large, diameter larger at tip than base), BP (Brood Patch )(0-5 for vascularization and wrinkles—evidence of brooding), Weight in grams, Wing Length in mm, Tail Length in mm, Culmen (Beak) Length  in mm (two measurements are taken for hummingbirds), Molt (1 = primaries or secondaries, 1-6 = molting symmetrically, 2A= no evidence of sequential wing molt, tail and wing feathers faded and worn; 2B = no evidence of wing molt, tail and wing feathers fresh), Ectoparasites (1 = none, 2 = tick, 3 = mite, 4 = lice, 5 = hippo, 6 = more than 2 types, 7 = unknown parasites), New or Recapture, Tarsus Measurements in mm (we do not measure the hummingbird’s tiny tarsus), Furculum Fat, Abdominal Fat, Body Molt (N = none, M= medium, H= heavy), Juvenile Plumage (estimated percentage), and Notes (any feather or color discrepancies noticed; oddities such as “missing all tail feathers,” “tick near left eye” etc).

When a bird is caught, it is handled with what's known as the "bander’s grip." This hold in which the head is between the first two fingers and the bird’s feet rest on the curled thumb, keeps the wings folded against the body and allows the naturalists to check the general condition of the bird, including its age and sex. The condition of the female indicates whether or not she is incubating eggs. If the brood patch shows that the bird is actively brooding, it is banded and then immediately returned to the spot where it was captured.

We are also taught how to how to hold a bird in the “photographer’s grip,” its feet secured between our fingers as shown. Hummingbirds cannot be held this way as it could damage their tiny legs. Most hummingbirds are photographed as they perch on a volunteer’s hand or as they are held loosely and offered nectar after being banded.

To weigh the regular birds, we weigh the bagged bird; then weigh the bag and subtract the bag weight from the total. To weigh the hummingbirds—the smallest weighing under 2 grams—we put a piece of fine mesh and clip on a scale, zero it, and then wrap the bird in the mesh, secure it with the clip, and weigh the wrapped bird on the tared scale. Stacy Peterson, an Eagle River, Alaska, hummingbird bander, says she simply lays the hummer on its back on the scale. She claims that the bird lies still to be weighed 95% of the time.