Fire is an integral part of life in the Northern Territory, and particularly in tropical savannas. In fact, tropical savannas are what they are in large part because of fire. Without periodic burns, grasslands with sparse trees would quickly develop into forests.
Our study site is located in a private property near the Coomalie Creek. The land owner conducts regular “cool burns” at the end of the monsoon season in order to simulate a natural fire regime and so that if fire were to start it would not get out of control. These creates a mosaic of burned, recently burned, and unburned habitat, with burned areas and roads both acting as fire breaks if a dry season fire were to sweep through.
Living in the land of fire became a little more familiar to all of us in the past month when a fire that started near Adelaide River (likely started by “weekend warriors”) came up north to our study site, ultimately burning about half of our study area and coming within a kilometer of our house! The day started off as normal: waking up in the dark, eating breakfast in the dark, and heading out into the field in the dark. I drove up into the middle of the site and got out in order to listen for birds (along with Mitch and Tess) that we would try to catch with mist nets. Kelly also got out to start heading towards the start of one of her occupancy model transects. It was still dark, but the smoke in the air was thick and we could hear the crackling of fire. “Guys, I think that fire is really close,” said Kelly. “Nonsense,” I replied, “It’s just an illusion. I’m sure it’s kilometres away.” “But I can see the flames.” Sure enough, looking through the trees the orange tips of flames were visible. “I’m sure it won’t affect your transect, go ahead and head in the direction” I told Kelly. Kelly headed off in the direction of the fire and we dispersed to listen for birds, but a few minutes later there was a crackling on the radio. “The fire is right here!” said Kelly. We drove down the road to meet up with Kelly and the fire had already burned a good portion of “the horseshoe,” a popular part of the study for wrens and the spot where we saw our first flock as a group. That part of the fire burned out later in the day, but another finger of the fire coming from the south jumped a fire break and came up through the center of the site, burning an area filled with dense gamba grass, an exotic species introduced from Africa that has tremendous fuel load potential. We missed seeing the actual flames because it all happened so fast, but the area that was home to a fair number of the birds that we had banded was completely gone, with only blackened earth and lone silhouettes of eucalypts remaining, some still burned logs, and a few tufts of grass that managed to escape the flames. Only hours after the fire the wrens were active, and we witnessed birds that afternoon and the next morning contact calling persistently in the area of the burn. However, after a day they had all dispersed; some of them we have resighted in adjacent unburned areas and others of them are still MIA, but are sure to be found. By marking the locations where the birds were captured and where we resight them throughout the birds lifetime, we will be able to see not only how the birds respond immediately to fire, but also if they return to their original territories once the grass regrows or if their temporary relocation becomes permanent.
I just realized that I don’t have any photos of the fire or the aftermath, so stayed tuned for some at a later date. For now, here is a picture of the crew in Kakadu with a fire in the distance and of some smoke from a more distant fire (that one wasn’t an illusion) from the airstrip.