Taking pulse of ecosystem through birds
By Emma Shelly
Dec. 28, 2017 at 10:18 p.m.
Updated Dec. 29, 2017 at 1 a.m.
The saltmarsh sparrow is a ruffled brown ball in the net, hanging docilely in the meshing as I work to free it. It hasn't been in the net that long so it isn't very tangled but there's still an art to getting it out of what we call "the pocket."
Holding it in my left hand, I free its feet first then its wings and finally its head and the bird comes out a little confused and disheveled but unharmed. From here I slip it in a special fabric bird bag and take it back to the station to band and measure.
That's what I did during my grad school summers: band sparrows. Adult sparrows, young sparrows, saltmarsh sparrows and seaside sparrows, every sparrow I could net in the marshes of Connecticut.
Back then, I was banding birds for my research; we band birds here at the Gulf Coast Bird Observatory, too, even though no one here is pursuing a graduate degree.
If you visit us the third Saturday of every month, you'll get a chance to see both the nets and the banding process up close. The nets, called mist nets, are made of fine mesh. If there is no wind to move them, they hang almost invisibly against the backdrop of the woods. Birds fly into them without seeing them and are then extracted (or freed) and carried back to be processed (banded, measured, etc.) before release.
When we catch a bird, the most important data to collect right away is the species and band number. Each band has an individual identification number and, in the U.S., the USGS administers the banding program ensuring that all numbers are registered. Most bands are made of aluminum and sit above the bird's foot like an anklet. They come in different sizes for different sized birds, and we close them around the leg with a pair of special pliers.
The whole banding process might seem a little strange without knowing the why of it all, but banding is a fantastic way to collect data. It tells us so much about the individual birds we catch, and the longterm trends of the area we band in.
Field measurements give more information about the individual bird. Wing and head measurements are good estimates of size. Blowing on the stomach to look for fat stores beneath the skin is a good indicator of how fit the bird is, especially during migration. And, of course, if the bird is a recapture, we can read its band number and look up when and where it was banded originally.
For example, last month, we recaptured a buff-bellied hummingbird female that was first banded at the Gulf Coast Bird Observatory on Nov. 21, 2015, as a juvenile that had just hatched that year. Catching her again in 2017 means that this is the third winter she has graced us with her presence. How neat is knowing that she survived and is returning to winter with us again and again?
As interesting as all this information is, I've always loved the longer term implications of banding data. Take the Gulf Coast Bird Observatory property, for example, which was once a DOW park for employees. The park had a softball field and other recreational facilities and while it was definitely tree-filled, it wasn't anywhere near as natural a habitat as it is now.
When DOW gifted us land, there was an agreement that Gulf Coast Bird Observatory would work to restore the habitat and, more importantly, track the success of that restoration. So our wetland was excavated and populated with vegetation, the courts were removed, plantings took place and the area became the Gulf Coast Bird Observatory we have today.
The question is how do you measure whether or not all that work had any impact? Sure, the ecosystem looks better, but that's not a definitive answer. Is it actually healthier? One of the easiest ways to scratch the surface of that tough question is by banding birds and looking at the trends. Are we catching more birds and more species of birds today than we were at the start of the restoration? Are these birds resident birds that are staying with us year after year? Do the birds we catch look healthy? Is our property attractive enough to migrants that they use it as a refueling station?
The answer to all of these questions is a resounding yes. If you go back through the observatory's banding data from almost two decades ago, you will see an uptick in the number and diversity of birds we're catching on site.
It is a cool thing to realize you can take the pulse of an ecosystem - no matter how big or complex - by turning to its birds for its heartbeat.
Emma Shelly is the Education and Outreach Manager of the Gulf Coast Bird Observatory. The GCBO is a nonprofit organization dedicated to saving the birds and their habitats along the Gulf Coast and beyond into their Central and South America wintering grounds.