We knew it was too good to be true. On the first day of trapping, we set our net in a section of the Panaquatira beach close to a site where we caught 85 ruddy turnstones last year. Our success depends most on catching turnstones, and most importantly, re-catching the ones we affixed with geolocators last year. We knew the geolocators had accumulated a full year of movement data and hoped to catch more than a few during our trip. With this effort, our team could create a new emphasis on the migratory ecology of ruddy turnstones, a Rodney Dangerfield-type shorebird that rarely gets the respect it deserves.
Interestingly, more data on turnstones could actually help human health. The majority of our funding for this trip came from the National Institute of Health because turnstones are virology superstars. It’s not because they threaten human health and thus deserve the NIH emphasis, but because they help can shed light on how viral infections spread across continents. Dr. David Stallknecht and his students from the University of Georgia have been working on shorebirds in Delaware Bay and other important sites in the US, trying to understand the complex interaction of migrant birds and viral infections, including H5N1, the notorious bird flu. He helped convince the NIH to fund our work here in Brazil.
Our optimism regarding catching birds springs from our focus on wintering shorebirds. Usually we try to catch birds on migratory stopovers, say the southbound flight at Monomoy National Wildlife Refuge in Massachusetts or the northbound flight through Delaware Bay. In these places we have less chance of re-catching a bird with a geolocator because she might use the stopover one year and then use different habitats (or skip the stopover altogether) the next year. Behavior at a stopover varies.
This variation is less likely in wintering areas. Most shorebird species go to the same place every year. Some birds, like piping plovers, set up a wintering territory in the exact same place each year, sometime within a few meters of the previous year’s location. Because of this, the chances of encountering the same bird year after year are much higher in wintering areas. Moreover, ruddy turnstones distinguish themselves as being among the most site-faithful.
So we expected to catch birds and geolocators with only reasonable effort. We didn’t expect the birds to run from us. It started not long after we made our first net set. It’s a lot of work: laying out the net and camouflaging it, digging in the cannons, testing the circuit, locating markers. It’s a routine for us, but hard work as well. Soon after we completed the set, a ruddy turnstone flock of about 180 birds with 25 geolocators flew in from the south and roosted along the tide line, only 50 yards from the net. Our hopes buoyed, than fell. The birds took off and never returned., despite considerable effort to convince them otherwise.
Then they threw us off totally. Over the next few days, we set our net several times in the usual places, but the birds either didn’t show up or wouldn’t stay. We spent an entire day combing beaches from São José de Ribamar to Panaquatira, no small feat in this land of horrible roads and extraordinarily difficult beach access.
Where did they go? We were like athletes on a losing streak and we only had one week left to do the job we came to do. So it was as we left the house in the predawn darkness to set the net once again, this time with little hope of success. As the dawn sun broke through pastel red clouds, we sat ready to catch.
At first, no shorebirds came to what seems a postage stamp size net (in fact the net measures 18 meters by 10 meters). The tide soon flooded the catch area, the sun clouded over, and gray clouds sprinkled us with a warm rain. Than a few black-bellied plovers flew to the point, followed by several small flocks of turnstones, sanderlings and semipalmated sandpipers. Before long we had a flock. Mark Peck brilliantly twinkled them (moved them) them into the catch area of the net, and in a second we had a catch of turnstones, four with geolocators.
Now we can spend time on catching knots.