Learning how to capture and band birds for SMBC’s Neighborhood Nestwatch program

SMB’s research scientist Pete Marra demonstrates good bird handling form, with a veery in hand

Greetings from the DC area! … Pictures (and other content that I want to post) have slowly been piling up, so I want to spend at least a few minutes of this fine Sunday morning making at least one post describing what we’ve been up to.

The first ten days with Nestwatch have been kind of an “orientation” — getting to know your coworkers, filling out lots and lots of paperwork, picking up vehicles, and getting practice with mist netting and bird banding. We even had our first and second real Nestwatch visits this week! More about that later.

Although I’ve volunteered as a bander at the River Bird Observatory in 2010 and 2011, I only had time to band once or twice a week, and processed only about 60 birds total (over the course of two banding seasons). Also, before this summer, I had never set up or taken down mist nets before (I had only open and closed them). While it’s not difficult, there are a lot of details you have to pay attention to in order to make the process go smoothly. (Since the nets are so thin and light, you have to be mindful of how you bag them up, or else they can get “tangled” — not knotty necessarily, but not able to unfurl in a “smooth and orderly” way.) … Anyway, I feel like I’m getting a lot of useful little additions to my bird-handling skill set.

Today I want to post some pictures that show how we band birds.

Set up Mist Netsts

Most bird banders use nets to catch birds. These aren’t ordinary nets, though — these bird-catching nets are nearly invisible nets that are strung across two poles.  They are like a large rectangular hair net, but the mesh is fine like spider silk. The nets are strategically placed in shaded areas, or next to vegetation, in order to help conceal them. These fine, lightweight, nearly invisible nets are called mist nets.

Ideally, you set them up (or open them) just before dawn because (1)  the nets can’t be seen because it’s still dark, and (2) dawn is when birds are most active.

An aside: Morning people who like waking up before 5:00am make good bird banders! I’m slowly getting there…

Here’s a picture of our team setting up some mist nets on the hill just outside the Smithsonian Migratory Bird Center:

Setting up mist nets, as two white-tailed deer look on

Sticking a mist net pole into the ground — setting it up in a lane where two cardinals are nesting:

Using some elbow grease to sink the pole into the ground

After the net is open, you have to “clean it up” and make it look invisible by plucking out the wrinkles and debris:

Plucking the net to smooth it out. Can’t see the net? Good! Neither should the birds.

After you set up the mist nets, banders usually retreat for 10 – 20 minutes and wait for birds. Birds will, for the most part, avoid the area if there are people lingering there.

An Outdoor Laboratory: Tools of the trade

Nestwatch banders band birds outside. Here’s the kit we use:

I think most of the kit is pretty self-explanatory. Still, I’ll try to find a photos of the kit in use.

The Process

1. Remove the bird from the mist net:

Female common  yellowthroat in a mist net; photo by Kelly Miklavcic

2. Put the bird into a cotton drawsting bag – this protects it and calms it down. (Sorry, I forgot to get a picture of the bag!).

3.  Weigh the bird. (We measure the y bird in the bag, and then remove the weight of the empty bag to calculate the bird’s weight.)

Birds are pretty light. Just for fun, some weights of birds:

Source: All About Birds, US Mint Coin Specifications

4. Prepare and apply the bands:

Each bird gets a different sized band; photo from NationalBand.com

Unique combinations of color bands  make the bird possible to identify from a distance

American robin with color bands I actually saw him by the national mall, not by the zoo, just yesterday! I’ll have to go to this website and report him

The above robin has white over pink on its left leg, and aluminum over pink on its right leg; this would be notated as  W/R, A/P.

5. Measure the wing chord (shoulder to end of first primary), tail length, and tarsus (leg).

Measuring the wing chord of a Veery

Measuring the tarsus the “lower leg” on the bird.  A bird tarsus is actually a fusion of several foot bones that currently still remain unfused on other animals (example: tarsals and metatarsals) so is sometimes considered part of the foot of the bird, and not the actual leg

What most people think is the “knee joint” is actually more like an ankle joint.  The knee joint is actually tucked up close to the bird, under its feathers (#7):

It is a myth that birds’ knees bend backwards! The “knee” we see is actually an ankle joint

The tarsus is a good indicator of body size, since weight can fluctuate depending on how much the bird has eaten or if it’s carrying an egg.

Usually, to get an accurate measure of the tarsus bone, we have to gently bend the toes (to see where the tarsus bone ends, and the toes begin). Sometimes, the toes are too scaly to bend; scaly feet are a symptom of  avian pox. Here’s a picture of an American Robin with a case of pox.

6. Check for fat – When most people take a vacation in a foreign country, they ride in a big jet and  enormous amounts of fossil fuels. When birds journey to a different country, they use a little pair of tiny wings and a store of fat (that must be constantly refilled along the way at “migratory stopover sites” — like your backyard).  We want to check how full the bird’s “fuel tank” is, and we do it by blowing into the groove right below their neck (which is where the furcula, or “wishbone”, is)  and checking for fat pads. We rate the fat from 0 (no fat) to 5 (bulging).

Migratory birds are constantly burning through fat, and so usually have no fat pads (or trace amounts).

7. Check for a brood patch – The brood patch is an area underneath the bird that doesn’t have feathers; instead of feathers, there is a patch of exposed skin which is used to transfer body heat to eggs (skin to egg contact).

The presence of a brood patch usually indicates a female; it also means that the bird is sitting on eggs… it has  nest somewhere!

A white-breasted nuthatch with an area of exposed belly, or a “brood patch”, used to transfer heat to eggs

If we find a swollen cloaca (the “hole” out of which birds  defecate and copulate), we have a male bird in breeding season. Females rarely have such swollen cloacas. This guy has a pretty good blog entry about how cloacas can be used to determine the sex of birds.

8. Write down and double check your data. Include notes about plumage, eye color, or any other notable features of your bird.

9. Release the bird!

Here are some birds we captured/banded this week:

Gray catbird with colored bands

Female American Robin – being handed to one of the interns  to “let go” (banders don’t ordinarily accept birds with open hands like this)

Veery — a thrush with “veery” few spots

Eastern towhee – female

Another of the eastern towhee – note the white spots on the tail

Northern Cardinal – male; photo borrowed from Kelly Miklavcic!

Common yellowthroat, male

White-breasted nuthatch; photo by Kelly Miklavcic

Common yellowthroat – female

Tufted Titmouse

Common Grackle

Another  – I love grackles!

That’s it for now. Writing about it helps me remember the process,  but maybe it has taught you something, too. (I really want to write another post about why we do bird banding, but that post is going to require a bit more research and time than this post did.) Next week, we are going to practice getting mist nets up and down perfectly  (without using stakes or ties) and get our methods critiqued in a sort of “banding bootcamp”… and I can’t wait. (If only all examinations were this useful/fun.)

Anyways, I hope you enjoy learning a little bit about the bird banding process, and thanks for reading!


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