Birdwatching - for bodies (Australian Raven image above by James Preece, photography)
(Observing wildlife to locate human remains)
‘An old man’s alternative re-interpretation of a young man’s pastime’.
As we get older some of us get great pleasure in ‘observing', from watching people in the street, to dog’s territorialising the park, to children practising to be adults. Nothing much changes, the core elements are the same, only some confusion on values and behaviour is different.
Also, as we age, we think a lot more, maybe because it takes us longer to focus and fathom on anything, so we have to think and re-think, often about the same thing we forgot that we thought about yesterday.
My focus is on missing person cold cases in the bush or wilderness. I spend a lot of time thinking about what leads up to people going missing, how they became lost or missing, and why they are sometimes not found.
I am a big exponent of thinking, ‘what am I looking for’ and ‘what am I looking at’. Putting that into the searching for missing person context a lot of things come to mind, such as how we tend to forget what we are and from where we originated. Modern humans are, in the main, descendants of nomadic hunters and gatherers, who a long time ago, just like the old folk of today, observed, mostly nature. They were looking for food and, to understand the relationship between things, they needed to know if ‘what they were looking at’ was edible or a threat.
Old folk today are also nomadic wanderers, but unlike the prehistoric model, we spend our time wandering in our thoughts instead of the tundra. Anyway, enough of wandering and to the point.
In the old days, missing persons, whether voluntary or involuntary, fugitive or accident, were often tracked down using indigenous trackers, amongst which the Australian Aborigine and the Native American were renown. By the mid 1900’s we idiotically employed questionable ‘wisdom’ in devaluing and eradicating those irreplaceable skills possessed by the first nation trackers.
So, one hundred years later let us consider what some of those native skills were based on. I am not going to spear off in too much detail, but I will recognise that it was to some degree a skill set based on observations of nature passed down from generation to generation.
Search and Rescue (SAR) – scaling down
We have all read or heard the media reports that say, ‘Police are scaling down their search for ‘so and so, missing since last Friday etc.’ This comment usually means, that based on expert medical opinion regarding survivability of the missing person, the SAR team consider that it is unlikely that the missing person is still alive. There is no firm time frame for survivability, because so much needs to be considered such as, weather, age, health, clothing of the missing. However, in hard or extreme weather conditions likely to introduce hypo/hyperthermia it is often not much beyond five days.
Five days, or maybe longer is the ‘scaling down’ call, but we also know that some missing persons can survive a lot longer, one, two weeks or even more. But, what if they are dead, a lonely sleeper in the bush. It is not the end for family, who are left with an inconsolable grief and uncertainty. For them there is no ‘scaling down’, just a never-ending emptiness, often as lonely and desolate as the vast wilderness that has swallowed up their loved one.
The Natural Undertakers of the Bush
If we do not find the missing, the bush creatures will. Those creatures misnamed as scavengers are perhaps better tagged as sweepers, natural undertakers, or perhaps situationally tasked opportunists, who systematically and quickly turn the lost remains of a loved one into a temporary microcosmic eco-system of life and death.
First come the insects, flies and other tiny invertebrates, that respond to the first indication of death. These creatures are followed by small bush birds, ‘Willie Wagtails’ and others, who ‘follow and swallow the fly.’ Soon, as putrefaction sets in, the bigger birds, corvids and raptors, will come, most noticeably the Australian Raven, and in some Northern climes the kites and vultures.
The natural creatures of the bush will find the missing person we cannot, so are we so stupid as to not notice what is happening here. The stratum of nature finds what we are looking for without effort, some perhaps doing so by watching the behaviour of others and knowing that where feeds the fly will be the larvae. So why do we not watch the creatures and determine when they have found and are upon the missing person we are looking for.
On the contrary, we ‘scale down’ and withdraw at about the time that the natural discovery of the missing begins to take place.
What is the natural timetable?
I have recently been reading a lot of professional articles regarding taphonomy (hard to pronounce, but basically about what happens to a human body after death.) The interesting thing for me is understanding what stake the creatures of the bush have in the taphonomic process, which is hopefully something that can be considered for practical use in Search and Rescue (SAR) operations.
In studies put out by scientists from the Universities of Western Australia and Ontario Canada, there have been significant findings regarding the type of birds and other vertebrates that visit cadavers in the bush, and their various feeding patterns. The joint study, which in its preliminary phase was partially conducted in Western Australia, involved detailed observations of pig carcasses strategically placed in controlled areas. [i]
The observations and findings in the study mentioned above were interesting. Not only was there in many cases a distinct pattern of feeding on the pig carcasses by various creatures, but it was also noted that some species of birds dominated the visitation frequency to the sites. Of note was the Australian Raven, who was recorded as being one of the first visitors, appearing within a day of the fresh carcasses being placed in position. In the summer months they appeared to visit the carcasses for a feed in the morning, from sunrise to about 9.30am, and in the early evening from 4.30pm to sunset. However, when decomposition was at a peak, usually between 5 to 8 days after death, the ravens would also be seen feeding during the day. (See fig 1 below)
During Winter, the raven was still the most frequent visitor to the carcasses, however feeding was mostly during the warmer hours of the day, rather than mornings and early evenings as seen in the summer. (See fig 2 below)
Another active bird visitor to the carcasses was the Australian Willie Wagtail, who much like the raven, was there throughout the day. The willie wagtail’s interest was in the multitudes of insects and larvae feeding on the decomposing body. It is noticed that the Wagtail appeared in the winter months but not in the summer. It is suggested that this may be because there is an abundance of food available elsewhere in the summer, but not so in the winter months.
The raven was clearly the winner of the frequency stakes regarding the number of visits by the various creatures to the carcass sites, with about ten times more visits than second and third place which went to willie wagtails and the large monitor lizards.
Fig 1. (See footnote 1 for source reference)
Fig 2. (see footnote 1 for source reference)
What do the creatures feed on?
Most of the creatures involved in the studies are omnivorous, such as the ravens, lizards, foxes, dingoes and other scavengers, with many favouring the flesh as a diet staple. Other creatures such as willie wagtails and honeyeaters would primarily be feeding on the insect invertebrates who are in turn feeding on the carcass or its temporary residents.
Interesting observations have also been noted on some animals eating meat or chewing on bone that are not classified as carnivores. This includes some seed eating birds such as parrots, and deer, especially does that are known to chew bone to fulfil calcium and other deficiencies in their diet.
How do the creatures find what we cannot?
The question of how the various creatures find the carcasses is a somewhat open debate. We know that some birds, such as vultures and some seabirds, have a strongly developed sense of smell and can detect faint odour, to some degree like a dog, though nowhere near as advanced. However, most birds do not have a strongly developed sense of smell, it just varies according to species, and its effectiveness is reported to relate to the size of the microscopic olfactory bulb in the brain.
From antiquity to the present the raven has always been known to find food, similarly there has always been a suggestion that it is the raven’s sense of smell that assists in the food hunt, however the anatomy of its brain and olfactory system suggests otherwise, nevertheless experiments with ravens and buried food has indicated to the contrary that they do have a strong sense of smell. [ii]
Fig 3. (See footnote 2 for source reference)
When considering birds being able to detect odour from decomposition of a cadaver or animal carcase, it was suggested to me by some bushmen that the smell gets into the thermals and rises into the atmosphere. So, I looked at this possibility and did a lot of reading and asked a lot of questions.
One thing that I did discover was that there are hundreds of Volatile Organic Compounds (VOC’s) such as putrescine and cadaverine, that are produced by decomposition, and which have a molecular weight many times heavier than air, which perhaps suggests that there could be some difficulty in these VOC’s getting into the atmosphere? [iii]
I am further confused about the ability of soaring birds such as wedge tail eagles being able to smell VOCs, when I consider comments such as I acquired from Dr Penny Olsen (Internationally renowned ornithologist and author) who said, “…of interest is that many raptors, including wedge-tailed eagles, depend on thermals to carry them aloft. This means that they don’t get out and about prospecting for food until mid-morning or so.” Penny’s comments add to the thought debate that the thermals do not rise until the mid-morning heat gets up, which is when the raptors begin their high soaring ascent.[iv] Is it then that the eagles can pick up the odour from the VOC’s?
In discussing this topic with Dr Leo Joseph, Director, Australian National Wildlife Collection, CSIRO, he commented, “I remember two instances with Greater Yellow-headed Vultures in South America. Once in Brazil… I remember a dead sloth on the ground in primary rainforest with a completely closed canopy but there, perched not far from it were several Greater Y-h Vultures. And in Guyana when the Amerindians working with us shot a peccary and started butchering it, within minutes a Greater Y-h Vulture was circling overhead”.
The comment by Dr Joseph is interesting and is backed up by science and research, also following on with my own observations I recall some years ago on the edge of the Victorian Alpine National Park. We had just returned from cutting up a fallen tree trunk. The logs were outside of the cabin by the fire, and within minutes a great flock of red browed finches turned up and smothered the logs picking out the thousands of termites oozing from the broken wood. Within half an hour the birds had gone, and of all the years I have been in that country, that is the one and only time I have seen so many finches in the one place at the one time. What attracted the finches to the logs, was it the smell of the termites or the sound of a chain saw and the knowledge that cut wood means exposed grubs. I do not know what the attraction was. We have cut wood many times, and never seen such an infestation of termites, and never seen a flock of birds descend as if responding to a swarm invite on social media.
Further communication with Dr Shari Forbes (University of Quebec) added to the debate, in that even the carcass detection capability of birds of the same types eg vultures, can differ, with comments that the Canadian Turkey Vulture is known to use 'smell' to detect their food source, whereas the black vulture is known to use 'sight.' Dr Forbes states, "The behaviour is specific to the animal, not so much whether the VOCs are detectable in the air." Dr Forbes also explained that many animals, including trained cadaver dogs may respond to different VOCs in the air, not just cadaverine and putrescine.
Whilst the jury is still out regarding the level of sense of smell in some birds, we do know that the degree and level of VOC’s produced by the decomposition of cadavers or animal carcasses is quite high, and we can see that the visitation by various birds and other animals is high through the stages of fresh to bloat, putrefaction and skeletisation. We can also see the changes in visitation by some animals during the certain stages, for example the Willie Wagtail and honeyeaters in the winter months during the insect infestation of the decomposing body.
We can also see the differing visitation times for ravens, the most frequent visitors, between summer and winter. However, whilst there are differences, they are measurable and therefore somewhat predictable.
How can we benefit from observing?
We can see from the charts in Fig 1 and 2 above, that within a day or two of death the wild creatures begin to visit a cadaver or carcass. The number of visitations increases from about day two onwards and continues for up to 25 days or more in the summer months and 45 days or more in the winter months, which is when skeletisation is expected.
The activities of the various visitors may differ depending upon the state of decomposition, which may include heavy feeding on insects and larvae, or feeding on flesh by some ground dwellers such as dingoes, foxes or the large monitors, as well as the larger carnivore birds such as raptors and ravens.
The interesting thing from an SAR perspective is that the visits to the remains of a missing person will begin within a day of death and can continue and more likely will increase during the decomposition stage.
The concern here, from an operational perspective is that, as earlier mentioned, it is likely, due to the expiration of the survivability period, SAR may call off a search at the very point when animal scavenger activity is becoming noticeable on the body.
Therefore, rather than being the stopping point or reducing SAR resources at day five, it may be justifiable to leave a small group of specially trained personnel in the field to look for opportunities to locate the remains by careful observation of animals, predators and scavengers, and therefore recover those remains for examination and ultimate return to family.
Obviously, some of the challenges to SAR specialists may include, adverse weather conditions, a lack of wildlife, including birds to observe, or even the likelihood of wild or farm-stock animal carcasses in the search area. On that last note, a close examination of these other carcasses is encouraged as this may reveal exactly what sort of scavenger activity there is in the area.
The idea of observing scavenger birds to find missing persons is not a new concept, a quick read of Author Anne Marie Ackermann’s blog, ‘Ravens as Partners for Cadaver Dogs’ highlights many.[v] In more recent times in 2011 German police in Lower Saxony took the concept one step further by attempting to train Turkey Vultures to work with police handlers, however ‘vulture culture’ seemed to have worked against them and the project was a failure.[vi] It is interesting to note that some of the feedback to the bold German experiment including comments that perhaps they were using the wrong bird, and should instead have focussed on the raven, a highly intelligent and more human compatible option.
Regardless of any merits in trying to train ravens to work with Australian SAR specialists, that is not the focus here, the suggestions being more to at least observe wildlife in a natural environment rather than have them controlled and registered as ‘feathered and furred scouts and trackers.
Recommendations
The following is a list of recommendations that should be considered by SAR groups on bush or wilderness searches regarding the possibility of wild creature visits to the location of the missing person.
Establish (train and dedicate) wildlife observation personnel within SAR team.
Consult with locals and naturalists to identify relevant wildlife types and locations within the search area.
Consult with animal behavioural specialists to increase the relevant knowledge.
Consult with specialists in Taphonomy.
Consider wildlife observation activation from day one.
Include flight paths, nesting sites and game trails in the search area.
Leave a small operational team skilled in wildlife observation in the field after the main search is ended.
Note and map any animal carcasses in search area.
Be careful not to assume scavenger bird flightpath heading in direction of known animal carcasses as irrelevant, (follow up and search again as missing person may be in the same locale).
Cadaver dogs if available will likely speed up any location and search of an area suspected as being frequented by animal scavengers.
SAR wildlife observation specialists should also possess several skills which include the following,
Knowledge of types and behaviour of potential scavenger wildlife in the search area.
Location of rookeries or other roosting or nesting places, or dens of fox, dingo and others.
Knowledge of seasonal and weather impact on feeding patterns of scavenger wildlife.
Conclusion
This subject and the notes contained in this article is not put forward as an absolute ‘how to’ in locating missing persons, it is far from that. This article is provided to merely suggest SAR search teams attach another ‘gadget’ of thinking to their operational tool kit.
Many SAR teams will already utilise bush-skills in observing wildlife, most will likely do it as a legacy of experience, and some may already have it as a standard routine response. However, some may not have thought about it, or have moved more away from this category of basic outdoors skills to a new era of technology. My suggestion is that a continuing emphasis on the benefits that new technology provides is a definite, however we must not forget earlier skills that are still relevant. It is a pity that we discouraged the preservation of indigenous tracking skills and old fashioned in-the-field bush know-how. Generations of scientists have spent a partial lifetime re-acquiring knowledge for us that we could have picked up in a ‘heart-beat’ by listening to and observing the original and early bush-folk.
'Primarily amongst the knowledge not only lost, but in many cases discouraged by being totally undervalued, is the bush-skills of the indigenous and first nations peoples'.
Valentine Smith APM
Founder and CEO
M: +61 418 207 789
PO Box 1272 Surrey Hills North Vic
Australia 3127
[i] A preliminary investigation into the scavenging activity on pig carcasses in Western Australia by R. Christopher O’Brien, Shari L. Forbes, Jan Meyer, Ian R. Dadour. Humana Press Inc. 2007
[ii] Professor Gabrielle A. Nevitt of the UC Davis College, Department of Neurobiology, Physiology and Behavior, College of Biological Sciences Bodega Marine Laboratory, Coastal and Marine Sciences Institute.
[iii] Dr Maiken Ueland, Deputy director of the Australian Facility for Taphonomic Experimental Research (AFTER) at the University of Technology Sydney.
[iv] Dr Penelope Olsen, Honorary Professor, College of Science, Australian National University.
[v] Ravens as Partners for Cadaver Dogs by Ann Marie Ackermann, 3 June 2015
[vi] Michael Frohlingsdorf – SPIEGEL International 28 June 2011.
(Note: A special thanks to James Preece, Wildlife Photographer, Surf Coast, Victoria, Australia for provision of title image and other support.
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