1. Detection of birth and location of den sites in brown hyaenas (Parahyaena brunnea) based on GPS telemetry data Inga Jänecke Brown Hyena Research Project, Lüderitz, Namibia

2. Brown Hyaena
Brown hyenas are large carnivores, weighing around 40 kg. They are solitary foragers, but live in clans. Their cubs are born in dens and these dens become the social meeting point for brown hyenas of a clan when they are active. Here they socialise, play with the cubs and most importantly carry food to the dens to supplement the diet of the cubs.

3. Denning Communal Den Ø 7 natal and 7 communal dens per clan
We find two different kind of dens. The natal den, where the cubs are born, is inconspicuous and hardly shows any sign of hyena presence. Here, they are only visited by their mom to nurse.
When the cubs are a couple of months old, they are carried to a larger communal den. Here they meet other clan members for the first time and sometimes also other cubs. Communal dens have several entrances, which can lead to separated chambers and one finds an enormous amount of bones and carcasses around the den.
In our study areas, we find on average seven natal and seven communal dens within a territory. Distances between dens can be great and we have recorded moves between 150 metres and 15 kilometres.
Ø 7 natal and 7 communal dens per clan
Distance between dens when moving: 150 m and 15 km
Natal den

4. Objectives Detect estrus and duration of courtship/mating
Determine parturition date
Determine den site locations and occupancy at dens
→based on GPS telemetry data for population monitoring
The objectives of this on-going study are to analyse our long term GPS telemetry data to
To detect estrus in brown hyenas and occurrence of mating events or courtship periods, a subject I won’t talk today about, but
To determine parturition dates
Determine den site locations and occupancy at these dens

5. Methods: GPS telemetry
In order to reach these aims, we have collared brown hyenas with GPS telemetry collars since We collared a total of 12 different females and 17 males of 6 clans. Individual monitoring ranged from 3 months to 7 years, the average collar battery life lasting two years.
The majority of collars were programmed to take 24 GPS fixes per day, all on the same schedule.
Our first aim is set out to determine the birth data of brown hyena cubs through GPS data and for this, we look at GPS data collected from breeding females.

6. Detection of Birth This data is scanned for the following:
Date
Time
Latitude
Longitude X Y
21:00:00 11
22:00:00 17 4
23:00:00 16 3
0:00:00 14 5
1:00:00
2:00:00
3:00:00
4:00:00 10 1
5:00:00 29
6:00:00
7:00:00
8:00:00
9:00:00
10:00:00 2
11:00:00
12:00:00
13:00:00
14:00:00
15:00:00
16:00:00 13
17:00:00
18:00:00
19:00:00
20:00:00 21 18 6
Time Out 19 12 8
Date
Time
Latitude
Longitude X Y
15:00:00
Time Out
16:00:00
17:00:00
18:00:00
19:00:00
20:00:00
21:00:00
22:00:00 1
23:00:00
0:00:00
1:00:00 7 9
2:00:00
3:00:00
4:00:00
5:00:00
6:00:00
7:00:00 15 14
8:00:00
9:00:00
10:00:00 24 28
11:00:00 6
12:00:00 4
13:00:00 12 13
14:00:00 19
Date
Time
Latitude
Longitude X Y
19:00:00
Time Out
20:00:00
21:00:00
22:00:00 7
23:00:00 1
0:00:00 2
1:00:00
2:00:00
3:00:00
4:00:00
5:00:00
6:00:00
7:00:00
8:00:00
9:00:00
10:00:00
11:00:00
12:00:00
13:00:00
14:00:00
15:00:00
16:00:00
17:00:00
18:00:00 6
This data is scanned for the following:
Here you see a section of data that was downloaded from a GPS collar. Besides date and time information, we obtain a GPS location and movement information around the x and y axis of the collar. Regularly active hyenas show such a picture with little time out periods and what we are looking for when scrolling though our data sets are such periods: We are not only missing GPS data, the xy data also indicates that the animal showed very little movement. Finally, activity increases again, as seen here.
These time out periods provide us with amazing information:…

7. Birth Date
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On this graph, I present data from 13 litters of 5 breeding females. The y axis here shows the number of daily GPS fixes and as you can see, we have a sharp drop and hence many time out periods on day 15, which we have identified as the parturition date day and hence present two weeks of data prior and post parturition.
However, time out periods work well in our mountainous area, but brown hyenas in other parts of southern Africa may breed in more open spaces, so that time out data won’t easily reveal the birth date of the cubs.
A far better indicator is the daily distance that the breeding females move, which you can see here, as it drops to zero on the day of parturition.
We can now determine the exact age of cubs from images, like here in 2012, where the cubs were 5 months old and in 2013, where Alaika carries her 1 month old cub to the communal den.
However, for proper population monitoring and in order to protect sensitive brown hyena habitat, we also need to find the location of den sites.

8. 9 months months month

9. Finding Dens
Ideally, we need to collar breeding females to find den site locations, but to a certain degree, data of non breeding females and males can also be used, due to their strong affiliation to den sites. However, I will demonstrate how to find den site locations with data of a breeding female that has been collared since For demonstrative purposes, we chose only to use four GPS positions per day, as otherwise the following figures would be overloaded.
In order to find possible den site locations, we plot our GPS data on a map and create a polyline connecting successive fixes. We then visually identify interesting areas, where we find accumulations of GPS positions and crossing lines, such as at this northern site and this southern site.

10. Finding Dens
We then investigate these sites further and as you can see, most lines at the northern site pass through, whereas there is a clear pattern at the southern site, where we find multidirectional movement to one specific point, which is a typical indication of movement towards an active den site.

11. Occupancy at Dens quickly identify two den site locations
Day since parturition
Den
3-16
SP 3 Den
17-58
Jungle Den
59-69
69-76
77-80
81-116
quickly identify two den site locations
confirm by visiting
Once confirmed, we filter GPS positions taken at the dens, using a 100 m buffer around each den, due to locational error of the collars. In this specific case, we had already determined parturition date and could then determine which dens were used since parturition. As there were gaps in occupancy at these dens, we plotted all movement data for these dates. Not all dens are easily detected, as some are only used as intermediate dens when moving or they were disturbed without prior knowledge to the hyena, for example through camera trap set-ups.

12. Occupancy at Dens
Day since parturition
Den
Duration
3-16
SP 3 Den 13
17-58
Jungle Den 41
59-69 10
69-76
D-SPG27 7
77-80
Panorama 3
81-116 35 24 1 64
In this hyena’s case, the filtered movement indicated the location of two additional dens and we could fill the gaps in den site occupancy. The graph shows the days since parturition on the x-axis, with parturition date being number 0, and the number of GPS positions taken within each den’s 100 m buffer. Here you can see that there are some gaps where no GPS locations were recorded close to any den and I will explain this later on.
Since this is a long term study, we already knew the position of all these den sites and had camera traps set-up at all known natal and communal dens.

13. Days since parturition
Camera traps
Days since parturition
GPS
Den
Camera trap
3-16
SP 3 Den
17-58
Jungle Den
17-57
59-69
58-67
69-76
D-SPG27
68-75
77-80
Panorama
76-78
81-116
79-116
There were camera traps at four natal and four communal dens. We calculated the number of images taken at each camera trap per day and plotted those against time of parturition. Negative values indicated camera trap malfunction.
When comparing this graphs results with the number of GPS positions at the den, we retrieve very similar results, confirming that both methods work to monitor den site occupancy.
Now, coming back to the times, where GPS telemetry data was not very useful to determine den site occupancy, we can see, that this coincides with times, where we find many GPS time out occurrences, meaning that the GPS collar failed to obtain a GPS fix, which coincides with the determined parturition date as explained before.

14. Summary & Conclusions Age at first reproduction
GPS telemetry data provides information about brown hyaena
Parturition date
Location of den sites
Den occupancy
Natal dens
Communal dens
Inter litter interval:
Ø 11 ± 3.8 (SD) months
Range: 5.5 – 16.3 months
Litter size:
1.5 ± 0.5 (SD) cubs
Range: 1 – 2 cubs
Age at first reproduction
So all together, we are, with the help of GPS telemetry data, able to determine brown hyena parturition date, the location of den sites, den occupancy at natal and communal dens, the inter litter interval, which is on average 11 months in our study areas and in combination with camera trap data, litter size, which is between 1 and 2 cubs in our areas.
Therefore, GPS telemetry is a good tool to monitor brown hyaena populations and reproduction and also to
provide sound baseline data for monitoring brown hyaena populations through other means
GPS telemetry is a good tool to monitor brown hyaena reproduction
GPS telemetry provides sound baseline data for future non-invasive and more cost-effective monitoring (e.g. camera traps)

15. Acknowledgements Namdeb Diamond Corporation, Namibia
Nedbank Go Green Fund, Namibia
Predator Conservation Trust, UK
Namibian Environment and Wildlife Society, Namibia
Our work would obviously not be possible without our long-term sponsors, which are Namdeb, the Nedbank Go Green Fund, the Predator Conservation Trust and the Namibian Environment and Wildlife Society.

16. Helge Denker
Thanks and please feel free to ask questions.
Thank you!