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Draft Report On The Pel’s Fishing Owl

Date: 2007-07-31


Ground Survey Of The Olifants River, Kruger National Park


24th-27th June 2007


Introduction


A ground-based survey of Pel’s Fishing Owl (scotopelia peli) along the Olifants River in the Kruger National Park was conducted from the 24th-27th of June 2007 by two teams of observers from SANParks, Moholoholo Rehabilitation Centre, staff and volunteers from EWT-BoPWG.



This ground survey was the first to be conducted for the Pel’s Fishing Owl and other selected species occurring along the Olifants River in the Kruger National Park since the detailed surveys conducted by Keith Begg (unpubl. data) in the early 1990’s. It was preceded by an aerial survey of the entire river to identify habitats along the river with good potential for the species to occur.


Survey area


The survey was conducted in the riparian vegetation along the Olifants River in the central area of the Kruger National Park, stretching from the western boundary fence of the Park, known as Mamba Picket to the eastern boundary fence beyond Bangu Gorge, a distance of approximately 93km along the river.


The riparian vegetation in this area is dominated by tree species such as Jackalberry Diospyros mespiliformis, Natal Mahogany Trichilia emetica, Sycamore Fig Ficus sycamorus, Anatree Acacia albida and Weeping Boer-bean Schotia brachypetala. Shrubby vegetation of the lower stratum consists mainly of species such as Red Spike-thorn Maytenus senegalensis and Fever Berry Croton spp. Vegetation suited to the requirements of Pel’s Fishing Owl occurs sporadically along the course of the river.


Survey methods


Prior to the ground survey, an aerial survey of the river course was conducted using the Bantam Aircraft of the Conservation Section of the Kruger National Park piloted by Steven Whitfield. The survey flight took place on the 14th of April 2007. The aim of this survey was to identify areas of vegetation where Pel’s Fishing Owl was likely to occur along the river and to compare these with sites where the birds have been recorded during the surveys in the 1990’s.


The ground survey was conducted over a period of four days by two separate teams (see acknowledgements), with preference being given to the early morning, from shortly after sunrise until the survey was completed for the day. Each team consisted of 6 observers with 3 observers on the northern- and 3 on the southern bank of the river walking downstream and recording what they see. Table 1 provides a breakdown of the time taken, areas and distances covered per team per day.

















































































 

Area covered

Approximate

distance

Time

 

Western Team

 

 

Day 1 – 24.06.07

Mamba Picket to Cul-de-Sac

8.5km

6.5 hrs

Day 2 – 25.06.07

Cul-de-Sac to Xilandu

11.5km

7.5 hrs

Day 3 – 26.06.07

Xilandu to Maveen (Including a 3.6 km overshoot of the campsite)

18km

8.5 hrs

Day 4 – 27.06.07

Maveen to Wildevyeboom

9.8 km

5 hrs

 

 

47.8km

28 hrs

 

Eastern Team

 

 

Day 1 – 24.06.07

Wildevyeboom to Hardekooldraai

10.3km

6.2 hrs

Day 2 – 25.06.07

Hardekooldraai to Balule Campsite

16.5km

8.1 hrs

Day 3 – 26.06.07

Balule Campsite to Trails Camp

8.9km

4.5 hrs

Day 4 – 27.06.07

Bangu Gorge and area to Mozambique border

13km

6.5 hrs

 

 

55.7km

24.3 hrs


The team walked along the riverbank, scouring suitable looking trees for the presence (flushed birds or confirmed sightings) or signs of Pel’s Fishing Owl being present. Each team was divided into two to cover both the northern and southern banks of the river walking in a straight line at times extending to approximately 50-150 metres from the river banks on both sides depending on the extent of riparian vegetation. Tributaries with suitable vegetation were also covered for at least 100-500m from the main river depending on the nature of the vegetation. Regular radio contact was maintained between the teams and all relevant information was recorded on a Dictaphone carried by each team leader. Standard information recorded for all sightings or signs of Pel’s Fishing Owl were the following:


1. Time

2. GPS Coordinates

3. North or South Bank

4. Species of tree/s (if relevant) and description of site

5. Nature of sighting or signs (feathers, faeces, prey remains, roost, potential nesting site)

6. Number of birds


In addition to Pel’s Fishing Owl, sightings of other waterbirds and raptors were also recorded along the survey area. All relevant species of birds flying or moving past the teams in an easterly direction were recorded. No birds flying to the west or ahead of the direction of movement of the teams were recorded to prevent potential double counts. Field rangers accompanying the teams also took the opportunity of recording any sightings and spoor of certain game species, the presence of alien vegetation and other information.



Results


1. Pel’s Fishing Owl


A total of 9 Pel’s Fishing Owls were seen and counted during the survey while a further 24 sites were identified where positive signs of the birds’ presence were identified (Table 2). In addition, 5 potential nesting sites were located although confirmation of active breeding at these sites could not be confirmed during the survey.




































































































































































































































 

 

 

 

 

Pel's Fishing Owl

 

Date

Time

North/South

 

 

 

 

 

 

Bank

Visual

Signs

Nesting

Tree species

 

 

 

 

 

Site

 

Day 1:

 

24.06.2007 

 

 

 

 

Team 2

10:58

South

 

X(d,f,sc)

 

Ficus sycomorus

Team 1

11:00

South

 

X(d)

 

Trichilia emetica

Team 2

12:19

South

 

X(d, sc, p)

x

Ficus sycomorus

Team 2

14:35

South

 

X(d)

 

Diospyros mespiliformis

Day 2:

 

25.06.2007

 

 

 

 

Team 2

08:24

North

1

 

 

Diospyros mespiliformis

Team 1

09:15

North

1

X(f)

 

Diospyros mespiliformis

Team 1

09:44

South

1

 

 

Trichilia emetica

Team 2

09:55

South

1

 

 

Ficus sycomorus

Team 1

13:30

North

 

X(f)

 

Trichilia emetica

Day 3:

 

26.06.2007

 

 

 

 

Team 2

08:00

South

1

 

 

Ficus sycomorus

Team 1

09:17

South

 

X(f)

 

Trichilia emetica

Team 1

09:27

South

 

X(p)

 

N/A

Team 1

15:12

South

 

X(p)

 

Ficus sycomorus

Team 1

15:15

South

1

 

x

Ficus sycomorus

Day 4:

 

27.06.2007

 

 

 

 

Team 1

09:02

South

1

 

 

Breonadia macrocephala

Team 2

12:09

South

(Bangu)

 

X(f)

 

 

Totals

 

 

7

10

2

 


Key to signs: d = droppings/faeces; f = feathers; sc = fish scales; p = prey remains

With the exclusion of the known pair of birds just outside the western boundary of the Kruger Park, it is estimated that there are at most 4-5 active breeding pairs of Pel’s Fishing Owl along the Olifants River in the Park at present. This compares poorly with the findings of Begg (1992-1994) along the same river where a total of 18 birds were recorded and a total of 15 areas for potential for these birds to occur were found. The decline in sightings of prey remains and other signs of birds being present seems to confirm a decline in this species during this survey.


The results of this survey provide a good benchmark for comparison to the previous survey as well future surveys. Further studies are however required to confirm the decline and the reasons therefore, but the planned increased extraction and damming of water upstream for various purposes and the resulting decline in water quantity and quality could lead to a further decline in this species along the river.


2. Other birds


Ten species of diurnal raptors and two other owl species were also recorded during the survey. Table 3 compares the numbers of species recorded during the survey with numbers recorded by Begg (1991-1994, unpubl. data) while Table 4 reflects the numbers of additional species recorded by teams during the survey.









































































Species

Western Team

Eastern Team

Total birds

Recorded in 1992 survey (Begg, unpubl.)

African Fish Eagle

7

6

13

21

Giant Eagle Owl

7

5

12

8

White-crowned Lapwing

48

19

67

104

Goliath Heron

21

9

30

28

Yellowbilled Stork

4

0

4

140

Black Stork

0

1

1

3

Great White Egret

0

2

2

8

African Spoonbill

1

4

5

8

Saddlebilled Stork

2

5

7

5


Considering the distance of river covered, African Fish Eagle Haliaeetus vocifer numbers were rather low with 13 birds in total being recorded along the entire river. This reflects a decline of 35% compared to the 21 birds recorded by Begg in 1992 (unpubl. data.).


Seven Saddle-billed Stork Ephippiorhynchus senegalensis were recorded during the survey, a slight increase in the number of this species compared to the 1992 count. Similarly, Goliath Heron Ardea goliath numbers were slightly higher than the 1992 count. White-crowned Lapwing Vanellus albiceps seems to have a healthy population along the Olifants-river and 67 birds were recorded during the survey. This is however considerably lower than the 104 birds counted in 1992.























































































Species

Western Team

Eastern Team

Total birds

African White-backed Vulture

17

27

44

Hooded Vulture

15

17

32

African Hawk Eagle

4

2

6

Bateleur

11

5

16

African Harrier Hawk

4

3

7

African Goshawk

1

1

2

White-backed Night Heron

8

0

8

Martial Eagle

1

0

1

White-headed Vulture

2

0

2

Tawny Eagle

2

0

2

Brown Snake-Eagle

1

1

2

Marabou Stork

1

1

2

Little Egret

1

2

3


At least 28 active African White-backed Vulture Gyps africanus and 11 Hooded Vulture Necrosyrtes monachus nests were recorded along the river during the survey. Of interest were an additional two Hooded Vulture nests that seem to have failed due to apparent predation of the nestling in one case and the remains of an adult bird being found below another.


The low numbers of piscivorous bird species such as Great White Egret Egretta alba, Little Egret Egretta garzetta, Yellow-billed Stork Mycteria ibis and African Spoonbill Platalea alba is however quite worrying as these species were previously more common. A species regularly recorded previously, the African Open-billed Stork Anastomus lamelligerus was not recorded at all during the survey. The reasons for such low numbers of these species is worth investigating.


Conclusion


The data obtained from this survey are to be analysed in more detail using GIS technology and a follow-up report in this regard will be produced. There is however little doubt that the survey has been very successful and has provided us with valuable benchmark data for comparison to past and future surveys that could be undertaken in the area in future.


It is recommended that this survey be repeated annually to determine trends and changes in the population of Pel’s Fishing Owl along the Olifants-river over time. This also applies for other bird species of conservation interest that should be monitored. A proposal to this effect has been submitted to the SANParks Research Department at Skukuza.


Acknowledgements


We would like to extend our thanks to the Honorary Rangers: West Rand for kindly providing funding to carry most of the costs for the survey. Ashraf Sayed, of the Honorary Rangers: Johannesburg is also thanked for his participation in the ground survey. Other volunteers who participated in the survey were Corrie van Wyk and Stuart Robinson from the Moholoholo Rehabilitation Centre, Ken Kloppenborg (Colorado, USA), Morgan Pearl (Minnesota, USA) and Rael Loon, an Independent Researcher from Hoedspruit. Thanks also to Steven Whitfield for the aerial survey of the river course.



The SANParks Ranger Section is also thanked for their co-operation and assistance in making the survey possible. Thanks in particular to Freek Venter, Louis Olivier, Oupa Modirwa and Evans Mkansi for their support and to the following staff for their participation in the survey: Corporals Daniel Chavalala, Thomas Masiya and Elias Chauke and Field Rangers Elvis Shabangu, Thomas Mthonbeni and Solly Sithole. Thanks are also due to Andrew Desmet for his planning, participation and continued support for the survey. Staff from the Activities Section such as Donovan Terblanche and Philip Zitha are also thanked for their assistance.


The presence, participation and input of colleague L.D. van Essen was invaluable and assisted greatly in making the survey a success.


References:


Barnes, K. (ed.). 2000. The Eskom Red Data book of Birds of South Africa, Lesotho & Swaziland. BirdLife South Africa, Johannesburg.


Begg, K. 1992-1994. Unpublished data, Transvaal Museum.


Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds.) 2005. Roberts’Birds of Southern Africa. 7th ed. John Voelcker Bird Book Fund, Cape Town.


Tarboton, W.R., Kemp, M.I. & Kemp, A.C. 1987. Birds of the Transvaal. Transvaal Museum, Pretoria.


Tarboton, W.R. & Erasmus, R. 1998. Sasol Owls & Owling. Struik, Cape Town.


Pictures


Deon Harris (June 2007). Click on pictures to expand.


These pictures were taken on a trip to Kruger in June 2007. Here is an account of this trip by Msimeki Martin, Senior Field Guide at Olifants.



"I would love to share the experience of the life time from the clients we had on the river walk just East of Balule Camping site. It was the first time they had seen this beautiful rare bird, and it was enjoyed with great feeling. This experience shows how at Olifants, guides try harder to ensure that we meet some of our client "once in a lifetime" wishes. It is with great sadness that I think that there still people who do not appreciate bird life. To me personally, as the guy who grew up in the remote areas playing along the river hearing all the song sung by beautiful birds, it makes my heart sore.

It is not every day we meet clients wishes as there’s no guarantee about any sighting-it depends on luck and how much Mother Nature opens the window for us to see. The only thing we can guarantee is the landscape of KNP.


While we were watching this rare bird (the Pel's fishing Owl) the African Hawk Eagle tried to spoil our fun as it came at a high speed to catchthe bird as it took off when it picked us up. Mother Nature was on the side of this rare species as the eagle did not manage to catch it.


The picture of the bird in flight was taken as it was escaping the hawk and I give my salute to the lady who caught it in flight-more women should take up photography as a hobby. To Deon Harris and his friend may you grow from strength to strength in your birding hobby. We need more people like you who appreciate the small things. To Julius Mkansi my Head Guide keep the spirit. You are the man I always draw my strength from and the passion and your dedication hasn’t gone past unnoticed".

Credits


Compiled by: André Botha

Birds of Prey Working Group

Endangered Wildlife Trust

Private Bag X11, Parkview, 2122

Tel: (011) 486-1102

Cell: 082 962 5725

E-mail: andreb@ewt.org.za