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Eagle’s Eye Newsletter - June 2014 1

The Eagle’s Eye Newsletter

Birds of Prey Programme Endangered Wildlife Trust

June 2014

Eagle’s Eye Newsletter - June 20142

EDITORIAL

Dear Eagle’s Eye Readers

The 34th edition of the Eagle’s Eye electronic newsletter represents a great achievement. At this juncture I would like to give credit where it is due. I acknowledge the inputs made by Andre Botha the Programme Manager, his team and associates respectively.

The 10th Annual Conference of the EWT - Birds of Prey Programme was held in Namibia, Etosha at Eldorado Guest Farm in May 2014. When faced with the prospect of organizing a southern Africa congress for the first time in my life, I really had no idea where to start. Fortunately I gathered my thoughts very quickly and took the leap. From the very beginning I knew I had my work cut out for me but in the end, it all worked out beautifully. I sent out invitations, did registrations, gave advice, reconciled budgets, communicated with delegates and Eldorado Guest Farm, and organized transportation. I was also tasked with greeting delegates at the airport in Windhoek and directing them to the transport that was to take us from Windhoek to Etosha.

The event was well attended, useful information was shared and new avenues for collaboration were established. It was a wonderful exercise to organise an event such as the EWT- Birds of Prey Programme’s Annual Conference, but it did take a lot of effort and commitment to make it a success and I would like to extend my gratitude to all those who assisted.

I also personally want to thank all the delegates who attended for their outstanding support and response to the conference! I am so pleased with your cooperative attitudes that simply made the event a top notch event. A big thank you for making the event a huge success!

The date for the Annual Awards Evening of the EWT Birds of Prey Programme has been set for October 7, 2014 at the Johannesburg Country Club, Auckland Parks, Gauteng, at 19:00. I hope you are able to accept the invitation to come and witness the occasion.

Furthermore, please welcome two new team members of the EWT- Birds of Prey Programme, Jan and Cornelia Engelbrecht:

CONTENT

EDITORIAL ..............................................................................................................................................................................2

A VIEW FROM THE PROGRAMME MANAGER’S PERCH..........................................................................................................4

THE STATE OF THE OLIFANTS RIVER BASED ON OBSERVATIONS FROM THE PEL’S FISHING OWL SURVEY 2014.....................7

MONITORING RED-BILLED OXPECKER RELEASE SITES: MPONGO PRIVATE GAME RESERVE...................................................9

UPDATE OF THE MARTIAL EAGLE PROJECT IN KRUGER NATIONAL PARK...............................................................................10

WHITE-BACKED VULTURE NEST AERIAL SURVEY OF MOKALA NATIONAL PARK 2014............................................................12

CAMERA TRAPS REVEAL BREEDING BEHAVIOUR OF AFRICAN GRASS-OWLS.........................................................................14

ELECTRIC MARTIAL EAGLE PROJECT........................................................................................................................................15

SPONSORS..............................................................................................................................................................................16


Figure 1: Jan Engelbrecht, the new coordinator of the BoPP Kalahari Project

“We are Jan and Cornelia Engelbrecht, a couple residing in the Kalahari near the village of Askham. We are members of the SANParks Honorary Rangers at the Augrabies National Park and the Kgalagadi TFCA. We are very happy to work as volunteers assisting the EWT with Raptor monitoring and surveys in the Kgalagadi”. Jan and Cornelia will mainly focus on the vulture breeding areas along the Molopo River in the Kgalagadi.

The latest edition of Gabar Volume 25, No1, is now available and copies have been distributed to subscribers. Relevant articles for both journals Gabar and Vulture News, can be submitted to the respective editors Craig Symes ([email protected]) and Campbell Murn, ([email protected]) Best regards

Rebecca MabuzaAdministrator – Birds of Prey ProgrammeEndangered Wildlife Trust


A VIEW FROM THE PROGRAMME MANAGER’S PERCH

There have been many developments and activities associated with the work that the Birds of Prey Programme and its associates are involved in over the last few months and it is a difficult task to choose which highlights to focus on for my contribution to this edition of The Eagle’s Eye. However, most people will say that it is a positive sign that so much is happening, so here are a few events that I would like to share with you.

Our Savanna Vulture Project focused on tree-nesting vultures in South Africa recently entered into an exciting new partnership with the State Veterinary Services and the University of Pretoria when we received approval from SANParks to capture and track vultures in the far north of the Kruger National Park to assess the role that vultures play in the spread of diseases such as anthrax. To date, we have captured no less than 13 vultures using snares in the area between the Limpopo- and Luvhuvhu-rivers in the Makuleke concession area which forms part of the Greater Kruger National Park. These captures took place during an anthrax outbreak and there was certainly no shortage of carcasses in the veld where captures could be attempted. Apart from the fitting of tracking technology, tagging and ringing of captured birds, a range of samples were collected by the State Veterinarians which will be analysed for the presence of anthrax spores.

The analysis of vulture movement data will be compared to the rate and direction of spread of the disease during outbreaks to assess the role that these birds play in either the spread or limiting thereof. A disease such as anthrax could have a substantial impact on game and livestock populations and it is important to understand that role that vultures play in this regard in the Kruger. A number of the birds have dispersed from the area of capture in the first few months and have been recorded foraging in Zimbabwe, Botswana and Mozambique which, in some cases have provided interesting challenges in terms of the roaming capacity of the tracking technology used. Further captures will be undertaken in the coming months and we will keep you posted on developments in this regard.

Figure 2: A juvenile White-headed Vulture that was captured tagged and fitted with tracking technology

in the Kruger National Park

With the vulture breeding season currently in full swing, ground-based monitoring at various sites is also being conducted in earnest by all of our fieldworkers, partners and associates. We have been fortunate to secure the services of The Bateleurs to conduct aerial surveys of tree-nesting vultures at a number of sites across South Africa, the first of which took place in the vicinity of Kimberley and the Mokala National Park over the weekend of the 12th and 13th of July 2014. Thanks to Peter Hohne who made available his chopper and flying skills for the weekend and to Beryl Wilson who assisted with the navigation and observations during the survey. Other areas that we are keen to cover this year include breeding areas along the Molopo- and Limpopo rivers, Northwest and Zululand. We have also been fortunate to obtain approval to fly in the Kruger National Park to using the services of The Bateleurs and will be conducting our surveys there in September.


Figure 3: An African White-backed Vulture photographed on its nest during the aerial survey atDronfield

The Zululand Vulture Group is a partnership between the EWT, KZN Wildlife, Wildlife ACT, Raptor Rescue, Eskom and private landowners and works towards the conservation of vultures in an area that has in recent years experienced several incidents of poisoning which has severely affected populations in this part of South Africa. This Group formally met for the first time at the Ghost Mountain Inn, Mkhuze in late June 2014 to discuss their monitoring and fieldwork activities for this season. This initiative forms part of the KZN Vulture Conservation Strategy which includes the tagging and tracking of birds in the Hluhluwe-Imfolozi Park, Mkuze- and Phongolo Game Reserves as well as adjacent private land. This work has been conducted since 2005, but it has become essential to formalize the group and to focus the work conducted in a more structured manner. Future plans include the training of conservation staff and landowners in the prevention and management of poisoning incidents in the area and to improve the number of re-sightings of tagged birds in the area.

We have recently launched a new poster to promote the reporting of sightings of tagged vultures and colour-ringed Martial Eagles in the Kruger National Park. This poster will be put up at strategic places such as entrance gates, camp reception areas, restaurants and shops; and we trust that it will have similar good results to our poster featuring Southern Ground Hornbills. Please look out for this on your next visit to this area.

Figure 4: Our poster which promotes the reporting of colour-marked vultures and Martial

Eagles in the Kruger National Park


I was also fortunate to be invited to participate in the Workshop on the Poisoning of Vultures in Africa and Spain which was held at Algaba, Andalusia in Spain during the third week of April. The workshop focused on finding solutions and to share expertise with regard to the biggest threat to the continent’s vultures which currently contributes to the alarming decline in many populations of these threatened birds. It was a very rewarding learning experience from a number of perspectives and we managed to see lots of vultures and other raptors too! An unforgettable sight was more than a hundred Eurasian Griffons which came to feed on offal right outside the workshop venue and the substantial numbers of raptors returning to Europe across the Straits of Gibraltar on their northward migration at the time.

It was impressive to see how dedicated and effective the Junta Andalusia is in working towards the prevention, investigation and prosecution of poisoning cases as well as how effectively they use working dogs in the investigation of poisoning incidents. The visit to their analytical laboratory facilities in the city of Malaga was also a highlight. I trust that some of the lessons learnt during our time spent there, will contribute towards more concerted efforts in this regard throughout Africa.

A direct outcome of the deliberations at Algaba was the hosting of a Southern African Poisoning Workshop during the EWT-BoPP Annual Conference which was held at the Eldorado Guest Farm near Etosha, Namibia on the 21st of May 2014. Due to the sharp increase in poisoning in the sub-region over the last 18 months, it was essential to bring key stakeholders together to discuss appropriate strategies that will address the situation across the board, yet be applicable to meet the needs of each of the countries involved. I would like to take the opportunity to thank Dr José Tavares from the Vulture Conservation Foundation in Europe who kindly agreed to travel to Namibia to facilitate this workshop.

Figure 5: Eurasian Griffons arriving to feed at Algaba, Andalusia

I would also like to thank all the delegates who attended the 10th EWT-BoPP Annual Conference at the Eldorado Guest Farm on the 22nd and 23rd of May. We had a full programme of very interesting talks and the networking and social interaction after hours was also most enjoyable. Thanks also to Rebecca Mabuza and Holger Kolberg who were responsible for the bulk of the logistical arrangements and who ensured that the event went off without a hitch. We look forward to seeing you at the 11th Annual Conference which will again be held in South Africa next year. The venue for this is yet to be determined, but we will notify you in due course. The proceedings of both the Poisoning Workshop and the Annual Conference should be finalized and ready for distribution shortly.

Figure 6: Delegates to the 10th EWT-BoPP Annual Conference, Namibia – May 2014


THE STATE OF THE OLIFANTS RIVER BASED ON OBSERVATIONS FROM THE PEL’S FISHING OWL SURVEY 2014

The floods that occurred in January 2012 and a lesser extent during the early part of 2013 resulted in substantial changes to the Olifants River. Large tracts of riparian vegetation along the river were lost and some islands were completely destroyed. Most of the silt that ac-cumulated over the years was scoured out down to bedrock. Although this might seem detrimental to the system, the fish-eating birds observed during the Pel’s Fishing Owl survey this year as in the previous year, have shown an increase in numbers compared to previous years along the same stretch of river. The river is currently in a pristine condition and needs to be maintained as such.

Figure 7: Pel’s Fishing Owl ad Old Picnic Sport, Pafuri, Kruger National Park

We are sad to inform you of the resignation of Madel Whittington who was the coordinator of the Kalahari Raptor Project based at Nossob in the Kgalagadi TFCA. Madel and her family relocated to the Tsitsikamma National Park in the southern Cape and we wish her, Brent and Sabian all the best with their new assignment. Thank you for your contribution to the work of the EWT-BoPP Madel, we hope that you stay in touch. There is however some good news and that is the appointment of Jan Engelbrecht from Askham to take responsibility for this project. The focus of the project will however shift from monitoring raptor populations in the Kgalagadi TFCA to the monitoring of the African White-backed Vulture breeding areas along the Molopo in the southern Kalahari. These sites have not been covered in terms of monitoring since the passing of Abrie Maritz in 2010. Jan will introduce himself elsewhere in this edition. The annual surveys of the Luvhuvhu- and Olifants Rivers in the Kruger National Park were also completed during June 2014. Both surveys were completed without incident, and I would like to thank all the volunteers, SANParks staff and sponsors who made this work possible. We are currently working on the analysis of the data that was collected, and the report in this regard should be available shortly. The find-ings from the survey of the Olifants River is of particular interest due to the mining effluent spills in the Phalaborwa-area that occurred on a number of occasions over the preceding months and which caused the death of many fish in the river.

Finally, we would like to invite you to attend the Annual Awards Evening of the EWT Birds of Prey Programme which will take place at the Johannesburg Country Club, Auckland Park, Gauteng, at 19:00 on the evening of the 7th of October 2014. We look forward to host you there. For more details, please contact Rebecca Mabuza at 011 372 3600 or [email protected] Warm regardsAndré BothaManager: Birds of Prey ProgrammeEndangered Wildlife Trust


According to Roberts Birds of Southern Africa (7th edition) apart from human disturbance and water abstraction; siltation and pollution are the main threats to Pel’s Fishing Owls. Siltation of the Olifants River is mainly caused by silt collecting in the Lepelle Northern Water Barrage (LNWB) from upstream of an enormous catchment area (54 000km2). The LNWB supplies the Phalaborwa population with water. Unfortunately the river silts up and the barrage needs to be scoured periodically to increase the water capacity (at times the barrage only has 23% capacity). The current practice to break up the silt load in the barrage is one of slow release. These results in huge amounts of silt accumulating downstream. In the past scouring was only allowed during high floods, but this practice was changed due to the fish die-off immediately below the barrage.

Figure 8: White-breasted Cormorant Ads Olifant River, Kruger National Park

The results show that the Olifants River is more pristine this year than it has been for a number of years. Apart from the problem of siltation from the barrage, the Phalaborwa sewerage works are at times non-functional and the resultant overflow increases nutrient levels. This in turn leads to eutrophication of the Selati River which flows into the Olifants River. The increase in the number of Egyptian Geese (Alopochen aegyptiaca) indicates a proliferation of algae in the system.

Apart from the Pel’s Fishing Owl (Scoptopelia peli) which have been on a spiral down in numbers from the 90’s all piscivorous birds are benefiting the conditions over the past 2 years.

Of note was the extensive white-wash on the rocks along the river which is a good indication that certain species namely Reed Cormorant (Phalacrocorax africanus), Goliath Herons (Ardea goliath) are using the river for foraging for extended periods.

African Fish Eagle (Haliaeetus vocifer) numbers have doubled compared to that of the 90’s. Being, diurnal it is less dependent on thick riverine vegetation than the Pel’s Fishing Owl.

The Egyptian geese are benefiting exponentially due to the eutrophication, this species is aggressive in nature and could cause problems to medium size nesting birds along the river such as Hamerkop Scopus umbretta and, Hooded Vultures (Necrosyrtes monachus) by evicting birds from nests. In 2011 the population of Egyptian geese was 263 birds, 775 birds in 2012 and in 2013 it had increased to 933. In this year’s count the population had increased to 1116 birds.

With the pristine state of the Olifants River due to the scouring effect over the last few years due to the flooding, the operational procedure of the barrage will have to be reconsidered.

Scott RonaldsonCo-ordinator-Lowveld/KNP Large Birds Project


MONITORING RED-BILLED OXPECKER RELEASE SITES: MPONGO PRIVATE GAME RESERVE

In February, I visited Mpongo Private Game Reserve which is situated about 40km from East London. The reserve received 42 Red-billed Oxpeckers in 2009 and a further 19 in 2010. After some initial losses in 2009 owing to Vervet Monkeys attacking the birds in the holding boma, measures were taken to ensure that similar problems do not occur in 2010. A total of 36 birds were released into the reserve in 2009 and all 19 were released in 2010. Records of sightings of the birds have been kept since their release, although the effort of collection has varied, with some months having very detailed accounts and some having no records at all. Small groups of birds are being seen on a regular basis.

The preferred host species for Red-billed Oxpeckers at Mpongo Private Game Reserve are giraffe, white rhinoceros, domestic cattle and Burchell’s Zebra, with fewer sightings being recorded on buffalo and eland (as can be seen below). The domestic cattle are present on an adjacent property, also owned by Mpongo Private Game Reserve.

Figure 9: Total number of Red-billed Oxpeckers seen per host species or locality per year(Includes all recorded sightings from 2009-2014)

Several nest-boxes were put up as part of the standard practice for any Red-billed Oxpecker release. Six of these were found during the latest visit, although in some cases the stumps had shifted and the entrance to the nests was no longer accessible. These were re-posi-tioned to allow access and will be monitored during the next breeding season. The guides have, however, reported seeing juvenile birds on numerous occasions and suspect that the birds are breeding on the property.

Based on the sightings data and the feedback received from the guides, there seem to be a resident population of Red-billed Oxpeckers at Mpongo Private Game Reserve. Rodney Gerhardt, the conservation manager at Mpongo Private Game Reserve, is really keen on support-ing the project. He has assured me that the sightings data will continue to be recorded each month by the rangers and that a concerted effort will be made to monitor the nest boxes both prior to and during the breeding season. The current survey form, which we send out to any landowners requesting Oxpeckers, will be distributed by Rodney at the Maclean town Farmers Association meetings. This information will allow us to determine how widespread the Red-billed Oxpecker population is in the region.

I thoroughly enjoyed my visit to the reserve and would like to thank Rodney for his enthusiasm for the project and for hosting me during the assessment.


Figure 10: One of the ringed Red-billed Oxpeckers released on Mpongo Private Game Reserve(Photo: Cedric Gregson)

Leigh CombrinkCo-ordinator –Operation Oxpecker Project

UPDATE OF THE MARTIAL EAGLE PROJECT IN KRUGER NATIONAL PARK

We are now nearing the half way mark for data collection for the Martial Eagle Project - Kruger National Park (KNP) and we are rapturous to report that our team is making significant progress in the data collection phase of the project. Vital information is still being collected on adult home range use and movement ecology with the initial GPS tracking of six adults. Adult survival rates are being calculated based on a ringing and re-sighting programme, which has currently seen an additional 13 individuals colour ringed and released over the last 8 months. Our research into the habitat use, dispersal behaviour, threats, and survival of juveniles is also going smoothly with the tagging of 6 juvenile birds between December 2013 and March 2014. Finally a comprehensive breeding ecology study is currently running well into a second breeding season, with some interesting patterns emerging. These studies will all aim to determine the state of and impacts on Kruger’s Martial Eagle population.

GPS tracking of 6 adults has provided further insight into territory sizes in adults. Home ranges for KNP currently average 114 square kilometres. Birds are extremely territorial and home ranges from 2 birds GPS tagged in adjacent territories show very little overlap. Since their tagging, unfortunately both birds have succumbed to what is likely natural mortality. The birds were recovered sometime after the tags went offline due to challenges posed by swollen rivers and inaccessible roads brought on by the summer rains so determining the reason for mortality was troublesome. However, scrutinizing the GPS data it would appear the male entered deep into the neighbouring females’ territory close to her nest site and he was swiftly chased out. It is evident from the telemetry that the birds came into contact and the male went down hours later, while the female persisted for another 7 days before she came to her end after what would be classed as a territorial dispute. Studies on biologically similar Golden Eagles have also recorded losses due to territorial clashes. Records of Martial Eagles coming into conflict severe enough to result in death also exist with species such as White Headed Vulture and Bateleurs, and it is likely many more clashes of similar severity occur undetected.

Survival rates from colour-ringed adults are still to be calculated and this will still take some time as we wait for birds to be re-sighted.


Posters are now up in all KNP rest camp reservation areas in order to increase awareness and utilize tourists as citizen scientists. This has already reaped its rewards as 2 individuals that we have not re-sighted in 6 months were both photographed in the week following poster roll out.

Juvenile survival has been surprisingly good over the last 6 months with only one confirmed loss and one tag failure out of the 6 deployments. Unfortunately it was again not possible to recover the bird as the tag went offline; however a tourist report of a Martial Eagle juvenile carrying a GPS tag lying in the road with presumably a broken leg suggests the bird met enough force to disable the tag and bird simultaneously. This individual had only just dispersed from its nest near Orpen the previous week and had crossed over KNP into Mozambique before returning to KNP, where the tourists at Nwanetsi sighted it. Juveniles have shown large movements covering much of KNP and surrounding areas. A juvenile tagged at Lower Sabie spends much time in Swaziland and recently adventured off towards Inhambane, Mozambique. An individual tagged at Punda Maria spends much time south of Giyani in communal lands there. These land uses bring juveniles into increased risk of un-natural mortality, which may reduce recruitment into KNP. Finally, a late chick tagged on the nest in December has started making gradual movements away from the nest site, while the sixth and final bird has temporarily settled near Phalaborwa Gate between neighbouring adult breeding pairs.

Figure 11: Juvenile Martial Eagle movement map

Breeding success is much improved over the last season with 9 nests lined, 7 incubating and 2 brooding while 3 nests are inactive as they fledged chicks in the previous season and are unlikely to breed again this year. Seven (7) nests that were inactive last year have again shown no activity and no adults have been seen in those nesting, a region which raises some concern as to whether the territories are now vacant. Hopefully over the next year we will be able to start putting more pieces of the puzzle together and get a firm grip as to the state and ecology of Martial Eagles in KNP.

Rowen van Eeden PhD Student at Percy FitzPatrick Institute of African Ornithology, University of Cape Town


WHITE-BACKED VULTURE NEST AERIAL SURVEY OF MOKALA NATIONAL PARK 2014

Populations of most vulture species are so much in decline across large parts of Africa. In 2012 both Hooded Vultures and White-backed Vultures, which have both declined dramatically in recent years, had their conservation status’ uplifted two levels to Endangered by BirdLife International.

However, the conservation of vultures is particularly difficult as they are wide-roaming, highly mobile and susceptible to a number of mortality factors that include poisoning, wildlife trade, unsustainable harvesting for traditional and cultural use, electrocution and habitat loss.

In 2012, the Endangered Wildlife Trust registered a project with SANParks aimed at assessing and monitoring tree-nesting vulture populations in South Africa’s National Parks in support of regional conservation action. This Savanna Vulture Project aims to assess the population status of tree-nesting vulture species occurring within SANParks and to understand the dispersal and ranging behaviour of juveniles. Dispersing juveniles face a range of threats that are generally recognised, but need to be quantified, in order to establish appropriate conservation management actions.

Protected areas can play an extremely important role in the conservation of large scavenging raptors and their numbers and distribution are often significantly reduced outside these areas for most species. Although White-backed Vultures breed outside national parks, a significant (but currently unknown proportion) of their population is located within the SANParks network.

One of the four parks identified in this project was Mokala National Park, near Kimberley in the Northern Cape, and home to one of the six major White-backed Vulture breeding colonies in the area. Mokala, although only officially proclaimed in 2007, has had its vultures surveyed previously by Campbell Murn, now at The Hawk Conservancy Trust in the UK, in 2001 as part of his thesis. The land at that time was still both privately-owned and privately-managed, and today only part of the colony is located within the park boundaries. Whilst annual ground monitoring of the species has been undertaken since 2010, it was still uncertain where the full extent of the colony lies (both within the park and adjacent to the park), as well as whether there have been any significant changes to the number of breeding attempts in the population.

Figure 12: Mokala vulture nest aerial survey 2014 indicating route flown and previously recorded

colony boundaries

Following on from the previous micro light aerial survey carried out in 2001 by Campbell, a long-overdue aerial survey was conducted again in mid-July 2014 at the Mokala colony, as well as other colonies in the Kimberley region.

Repeating the exact same grid pattern as was previously used by Campbell, the 2014 survey was carried out using a Robertson R66 turbine helicopter owned and piloted by Peter Hohne, a member of The Bateleurs “flying for conservation” organisation. The crew consisted of André Botha from the EWT-Birds of Prey Programme who observed, captured electronic data and took photographs; and myself, zoologist


and field biologist from the McGregor Museum in Kimberley, assisting with navigation and written observations.Flying along the pre-panned flight paths spaced out at about 700 m intervals and at a height of between 80-120 m above the ground, all active and inactive nests were recorded. When visible, eggs and nestlings were also noted.

Figure 13: Re-fuel at Mokala National Park

Whilst the final results of the survey have yet to be analysed, the raw data obtained suggests that the area we covered on this survey is slightly larger at 160 km2 as opposed to the 120 km2 by the 2001 survey. Whereas Campbell recorded 69 nests in this survey, we recorded about 86. This appears to be an improvement but in the fact the nesting density has decreased slightly from 0.58 to 0.54 nests/km2. This is not particularly significant, but perhaps more noteworthy, the recent survey located new areas with nests not previously recorded in the ground surveys. This will significantly assist Ronelle Visagie, Birds of Prey field officer and I in the ringing and wing-tagging activities in October. Furthermore, it will help to determine the number of failed versus successful breeding attempts more accurately.

Whilst the results from the Mokala National Park population tentatively suggests that population estimates and nesting densities are stable, the same could not be said for several of the other colonies surveyed in the region, one of which recorded 27 nests in 2001 and now had none. Once again, this stresses the need for long-term monitoring. It also supports the theory that national parks and other protected areas may offer a stronghold for vultures and that their populations need to be monitored to assess their spatial and temporal responses to management action. More than ever, particularly in the face of the latest mass poisoning incidents, it is vital to learn more about what happens to young vultures when they disperse from protected areas in order to assess what threats they will be facing.

The 2014 survey team would like to express their deepest gratitude to the local landowners and the staff of Mokala National Park for allowing and supporting this survey; Campbell Murn for his logistical support; The Bateleurs and Eskom for supporting the operation, and especially to Peter Hohne for making himself and his helicopter available for the weekend.

Beryl WilsonMcGregor Museum: Professional Natural Scientist – [email protected]


CAMERA TRAPS REVEAL BREEDING BEHAVIOUR OF AFRICAN GRASS-OWLS

The threatened African Grass-Owl (Tyto capensis) is a secretive resident of inland freshwater wetlands in South Africa. The Endangered Wildlife Trust’s Anglo African Grass-Owl Project has been conducting research on the Grass-Owl in order to fill current knowledge gaps related to the species and its ecology. We are particularly interested in discovering more about the species spatial ecology, including the dispersal dynamics of juvenile birds from the nest. In order to find juveniles one must first find nests, which is easier said than done! During the late summer and autumn months they lay between two and six rounded oval-shaped white eggs in a roofed nest chamber central to a series of tunnels pushed into thick grass. This behaviour is unusual as most species of owl nest off the ground and do not construct their own nests but rather use vacant cavities in trees or nest structures built by other birds. The way that Grass-Owls tunnel into the grass makes their nests impossible to find in a sea of tall, rank grass unless the birds are flushed. They are also strictly nocturnal and give few vocal cues to help identify the territories of breeding pairs. Finding active nests has therefore been a tedious hit-or-miss task involving many kilometres of walking through thick vegetation.

A new approach to help us find more nests during the 2014 season has been to use a nest-site selection model constructed using data from previous years to identify potential nest sites. The model is proving to be an accurate predictor of breeding habitat in our study area and 11 new nest sites were discovered during only 20 days of fieldwork in April/May. The sites are generally very isolated and separated by many kilometres of mostly private land. Monitoring so many new sites on a regular basis would be impractical and time-consuming, so an alternative solution was required.

Figure 14: Male Grass-Owl defending nest in front Figure 15: Male roosting at the nest of the entrance with incubating female Camera traps were placed at some of the more remote nests in order to record breeding behaviour. The cameras are motion-triggered, taking one-minute videos every time there is movement in front of the sensor. Some interesting observations that have been made thus far include while the female is already incubating (Figure 15 &17) as well as both males and females making territorial vocalizations and displaying aggressive or defensive postures to other owls passing overhead (Figures 16). It has also been interesting to note the amount of time males spend at the nest. Males never helped with incubation, but spent a lot of time roosting at the nest entrance when not out hunting (Figures 15). When a male would be flying near a nest the female would almost constantly communicate with him by means of a clicking vocalization akin to that of a few clicking stream frogs. The camera traps also managed to record a few prey deliveries. Identification of prey items from the footage has, however, been difficult as they were often obscured by the male as he delivered them to the incubating female. The female greets the male with a continuous loud and deep hissing sound upon delivery of the prey which later turns into regular short, softer notes which is presumed to be a begging call. Nestlings make the same begging vocalization when adults are out hunting.

Figure 16: Male and female watching a passing Barn Owl Figure17: Male roosting at nest with female while incubating

Camera traps are great tools for recording wildlife behaviour remotely and are especially useful for obtaining footage of shy, enigmatic species. Female Grass-Owls have successfully incubated at all but one of the new nests being monitored and I hope to obtain some interesting footage of nestlings in the weeks to come.

Matt PretoriusCo-ordinator- Anglo African Grass-Owl Project


THE ELECTRIC MARTIAL EAGLE PROJECT

The Martial Eagle Polemaetus bellicosus is a strikingly-coloured, deeply impressive species. It is arguably the largest eagle in Africa, weighing in at up to 5 kg, and with a wing span of up to 2.4 m, and functions as an apex predator in a variety of habitats. The South African Martial Eagle population is thought to comprise about 800 mature birds, and current wisdom suggests that the densities of breeding pairs are generally higher inside the country’s largest game reserves and markedly lower in unprotected areas. Compounding this limitation, the latest bird atlas data (SABAP2) suggests a 59% decrease in the reporting rate of Martial Eagles in many areas of South Africa over the last two decades. These are concerning numbers, and have prompted the research community to look more closely at both the local and Pan-African conservation status of this iconic and ecologically valuable species.

Figure 18: Jessie Berndt holding a Martial Eagle Polemaetus bellicosus

While the Martial Eagle is generally a tree-nesting species, it has adopted a slightly different strategy in the open areas of the Karoo by nesting on the pylons that support Eskom’s power transmission network. Jessie Berndt is an MSc student at the Percy FitzPatrick Institute of African Ornithology, University of Cape Town, investigating this phenomenon, and what it could mean for the species given the present extent of the electricity network, and plans to expand it both nationally and across the continent. In collaboration with her supervisors (Andrew Jenkins, Res Altwegg and Arjun Amar), she is developing a statistical model to predict where Martial Eagles are likely to nest on pylons, based on a known distribution of nests derived from an earlier study of a sample of Karoo transmission lines. Once this model has been ground-trothed and refined, Jessie hopes to use it to estimate how many pairs of eagles are using the existing power grid.

(a) (b)

Figure 19: DSCN3011 is Megan Murgatroyd’s photo of Black Eagle project fame

Ultimately, the project aims to determine the relative importance of pylon-nesting in the long-term survival of the Martial Eagle. If this more adaptable aspect of the eagles’ biology is or becomes sufficiently widespread, it would motivate strongly for a corresponding adjustment in perspectives on the conservation biology of this globally threatened species , as well as a shift in the emphasis of associated research and management activities.

To find out more about the project please visit our Face Book page and www.facebook.com/TheElectricMartialEagleProject

Blog - http://electricmartialeagleproject.blogspot.com


The Birds of Prey Programme would like to thank all our sponsors for their ongoing support of the work done by our various Projects.

NEWSLETTER INFORMATION

The Eagle’s Eye is the quarterly newsletter of the Endangered Wildlife Trust’s Birds of Prey Programme and is compiled and edited by Rebeccca Mabuza

For enquiries, to submit an article or to unsubscribe, e-mail [email protected]

The articles in this newsletter represent various projects and individuals involved with the Birds of Prey Programme and do not necessarily reflect the opinion of the Endangered Wildlife Trust or the editor of this newsletter.

For further information visit:www.ewt.org.za

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