2017 | Northern Australia
Australian raptor (Milvus, Haliastur & Falco sp.) fire-stick foraging
Please note: Aboriginal and Torres Strait Islander readers are advised that the following post contains the names and words of people who have died.
Birds are dinosaurs. They can trace their ancestry back to before the planet-walloping asteroid some 66 million years ago, when bird-like dinosaurs wandered around with feathers, teeth and cousins such as Tyrannosaurus.
It wasn’t surprising, then, to see that the recent Prehistoric Planet TV series borrowed some known modern bird behaviours when speculating about those ancestors. For example, in one scene from the final episode an Atrociraptor is shown using a smouldering twig to apply smoke to its feathers, an anti-parasite activity seen in birds such as corvids that sit stop chimneys in urban areas:
Today, we’re looking at a second fire-related behaviour shown in that TV series. In the fourth episode, we watch as the relatively large-brained Stenonychosaurus carefully picks up a stick from the edge of a fire, carries it to an unburnt part of the forest, then drops it, igniting a new blaze. Small mammals flee the threat, unaware of the waiting dinosaur, and Stenonychosaurus pounces.
There is no direct evidence that either of these dinosaurs (or any others) used twig tools. But we do have extensive accounts of birds spreading fires in this way, seemingly deliberately. May I introduce you to the firehawks.
A warm reception
We’re in Northern Australia, a very large area that encompasses the tops of two states (Queensland and Western Australia), plus the Northern Territory of Crocodile Dundee fame. More specifically, we’re in the tropical savanna. And our cast for today’s tale is almost as large, with three species of fire-foraging predatory birds: black kites (Milvus migrans), whistling kites (Haliastur sphenurus), and brown falcons (Falco berigora).
Each of these species is well known for hanging around the margins of fire fronts, with blazes regularly started in the region either by natural means such as lightning strikes, or as part of land management practices by local humans. As the fire spreads, the raptors snap up any insects, lizards and any other small prey sent scurrying by the encroaching destruction, just as Stenonychosaurus grabbed a furry Cimolodon in Prehistoric Planet. Hence, firehawks.
Here’s some footage from Ngikalikarra Media of black kites foraging on the margins of a grass fire near the Fitzroy (Martuwarra) River, Western Australia:
The level of ecological adaptation shown by these birds is impressive enough, but throughout the past several decades there have been suggestions that much more sophisticated activities were going on. The stories shared among local First Nations Australians communities and fire rangers include repeated observations of the raptors deliberately transporting burning twigs to new locations, starting new spot fires. In 2017, Mark Bonta, Robert Gosford and their colleagues collected these reports into a database, which they published in the Journal of Ethnobiology.
To be clear, the relatively recent reporting of this fire-spreading activity only reflects its emergence into the consciousness of western science. As so often happens, the traditional knowledge of the local First Australians has understood and passed on evidence for intentional burning by firehawks for perhaps thousands of years. The scientific community has no claim to having ‘discovered’ the practice, a fact prominently acknowledged by Bonta et al. in their collaborative work with local people.
In an account published in 1963, for example, Alawa man Waipuldanya related his experiences with these birds in the region around the Roper River in the Northern Territory:
The kitehawks—we call them firehawks—are inventive hunters. Much of their natural food is caught and eaten on the wing, especially around the perimeters of bushfires where they swoop on fleeing grasshoppers. ... Firehawks often confused us in welcoming visitors to our tribal lands by deliberately setting fire to grass and bushland to assist their scavenging. I have seen a hawk pick up a smouldering stick in its claws and drop it in a fresh patch of dry grass half a mile away, then wait with its mates for the mad exodus of scorched and frightened rodents and reptiles. When that area was burnt out the process was repeated elsewhere. We call these fires Jarulan.
A very similar account comes from the Arnhem Plateau:
[K]arrkkanj the brown falcon…does more than just wait for the fire to burn into large patches of grass. This bird will swoop down, pick up a fire brand and fly off to drop it into another patch of grass. When a fire burns into a creek line and burns out, brown falcons have also been observed collecting fire brands and dropping them on the other unburnt side of the creek in order to continue the fire. This association of brown falcons and fire is celebrated in rituals.
There are sensitive issues around the use of traditional knowledge where it intersects with ongoing ceremonies or social restrictions, so the Journal of Ethnobiology report doesn’t cover all known instances of raptor fire-spreading. It does, however, include both Aboriginal and non-Aboriginal eyewitness accounts of the behaviour. These come especially from firefighters and people who manage controlled burns, who have spent extended periods in close proximity to the foraging birds.
As an example, one of Bonta and Gosford’s co-authors, Dick Eussen, was out controlling a grass fire when he saw:
a Whistling Kite flying about 20 meters in front of him with a smoking stick in its talons. It dropped the stick and smoke began to curl from the dry grass, starting a spot fire that had to be immediately extinguished. In all, he put out seven fires, all caused by the kites.
The collected reports, including that of Eussen, suggest that typically only a small number of individuals within a flock collect and redistribute burning or smouldering sticks. Further, not all apparent attempts to start a new spot fire (beyond a natural or artificially-created firebreak, for example) are successful, and in some cases it may be that the firehawks have accidentally scooped up a flaming twig when they were aiming for a panicked meal instead. Nevertheless, fire-spreading clearly happens often enough and across a large enough area—and over a significant amount of time—that its existence cannot be disputed.
For reference, if you’re looking out for the behaviour yourself, these are the black kite, whistling kite and brown falcon, aka the BBQ birds:
Fire farming
The twigs carried by these birds, either in their beaks or talons, aren’t sufficient on their own to accomplish the bird’s goal. For that, they also need to include a heating component such as a glowing ember or actual flame. This combination of elements means that firehawk tool use resembles a simple composite human technology, for example a stone tip hafted to a spear shaft, or a fishing look on a line. The birds appear to make opportunistic use of the co-occurence of the two elements—they don’t seem to be adding fire deliberately to the stick by holding it over a flame, for example—but it still marks an extra and non-obvious step in understanding the nature of the desired outcome. The aim is to transport fire, which itself is a proxy for prey in this case, with the stick acting solely as an intermediary tool or container.
Despite a flurry of news reports on the release of the Bonta et al. paper, academic interest in this topic seems to have remained fairly quiet. Let’s hope that the appearance of a dinosaur ‘borrowing’ the behaviour in a major TV series—narrated by living-legend Sir David Attenborough no less—will return focus to these fascinating firehawks, and bring further respect for the enormous corpus of natural history knowledge curated by First Australians and other indigenous peoples.
Sources: Bonta, M. et al. (2017) Intentional Fire-Spreading by "firehawk" Raptors in Northern Australia. Journal of Ethnobiology, 37:700-718.
Main image credit: Robert Gosford || Second image credit: Apple TV, Prehistoric Planet || Third to fifth images credits: Australian Museum & Museums Victoria