Another crucial skill for field ornithologists is being familiar with mist netting and bird banding. Stringing up mist nets is often the most effective way to capture birds, especially when used in conjunction with audio playback to draw in potential targets. The nets are usually placed between two trees or poles, creating a nearly invisible barrier for unsuspecting birds to fly into. They then become tangled in the finely-woven web, allowing for the biologists to step in and carefully remove them. Birds can be caught in this way for any number of processing procedures, including banding, physical measurements, and collection of blood or feather samples. They can also be turned into specimens.
Our Cardinalid project here in Tompkins County did not specifically require any data from netted birds. Our focus for this season was primarily on behavioral ecology, which can be observed in the bird’s natural setting. However, we still recognized our study site as a great location for learning the basics of mist netting. More importantly, it was imperative that the Borneo crew be well-versed in proper net set-up and bird handling, as much of the information they hoped to obtain in Tawau was dependent on the capture of individual birds. However, there was an additional snag that came along with this need: many of the target Bornean birds live at higher levels in the forest foliage. While mist nets are typically placed on the ground and extend as high as the poles they attach to, a significant number of the target taxa for Tawau are primarily birds of the canopy. As such, we were faced with the challenge of not only refining our basic net and bird handling skills, but also trying to come up with a way to catch higher-flying species.
The answer to this problem turned out to be surprisingly simple, largely thanks to the ingenuity of crew member Justin Hite. Using the tools at our disposal, we were able to design and construct an elegant and efficient means of placing nets at greater heights than usually possible. To begin, a “backbone” of p-cord was strung between two trees at the desired vertical level for the nets to hang from. This was achieved either by throwing the ends of the rope or using the large-size slingshots provided for us by the Cornell Outdoor Education department (COE). Next, full loops of p-cord were then attached to the “backbone” at either end. These loops were large enough to run from the ground up to the line, and they were fastened in such a way that they held their position horizontally while still maintaining the freedom to move in a continuous loop. Lengths of PVC pipe (with holes punched in them for attachment of mist net trammels) were then tied to these loops so they could easily be brought down to ground level or run up to full height. The ends of these loops would be tied to nearby trees to keep the nets taught, but could easily be undone to lower them on command. Once the nets were strung between these pipes, the system was ready for operation.
We set up several “net backbones” at various heights in different locations of interest. Our on-the-spot solution to a very important problem proved more effective than we ever expected. We caught a wide variety of species in our nets over the weeks, including Ovenbirds, titmice, and various thrushes. This allowed us the chance to practice extracting birds from the netting and processing them for data and banding. What’s more, our system was found to be surprisingly efficient even when capturing birds in the treetops. The total time it took from a bird hitting the net to returning the emptied net to position was only about 2 minutes. Mind you, that includes getting to the net, freeing the loops, lowering the PVC pipes and net, extracting the bird and placing it in a bird bag, running the nets back up, tying them off, and returning to the banding station! Not bad for a morning’s worth of crafting.
We can only hope the system we devised has been equally effective for our colleagues in Borneo!