Thank you to everyone who has submitted articles, photos and comments for this edition.
Please do keep sending all the sightings and information through, The Raptor is what YOU make it. In line with current eco-trends and aiming for a 'greener' lifestyle this is an e-newsletter - it does not conform to traditional page sizes and is not designed to be printed.
Another two tiny owls that occur on Raptors View are the African Barred Owlet and the Southern White-faced Scops-Owl. The African Barred Owlet can be confused with the Pearl-spotted Owlet that was featured in the May newsletter but it is a little larger (20-22cm vs 17-21cm) and is barred, not spotted on the head as well as the neck and breast, and it has no “false eyes” at the back of the head. The head is large and shows no ear tufts like the next species.
The larger Southern White-faced Scops-Owl (25-28cm) had bright orange eyes and distinctive ear tufts and clear black and clear white facial markings. The grey breast shows obvious vertical black streaks.
Both species feed on a wide range of invertebrates including beetles, moths, grasshoppers, crickets and scorpions as well as small mammals such as rodents up to the size of the Tree squirrel in the case of the larger Southern White-faced Scops Owl, as well as birds. The little African Barred Owlet also feeds on lizards, small snakes and small birds.
The call of the African Barred Owlet is a series of loud purring notes “kroo-kroo-kroo-kroo”, whereas that of the Southern White-faced Scops-Owl is a softer sequence of bubbling “bbooo” notes.
African Barred Owlet
Southern White-faced Scops-Owl
African Barred Owlet
Southern White-faced Owl Photo - Lee Gutteridge
Some Common Insects - Lee Gutteridge, RV164
There are many thousands of species of insects which will occur in our estate, but here are a few large and common species for you to identify around your home this summer.
Tapping beetles are known by many common names, such as Toktokkie’s and also Darkling beetles and belong to a family called the Tenebrionidae. These are flightless species which often attract their mate by means of a tapping of the abdomen (their bottom!) on the ground. They are mostly scavengers.
Another interesting creature I found in my garden last summer was a Leaf Rolling Cricket of the family Gryllacrididae. These creatures are usually flightless but here in the warm east we have some varieties with wings, such as this one. They use a type of silk to sew together leaves, in which they hide. This type of cricket is mute and might be carnivorous!
Leaf Rolling Cricket
The Clicking beetles of family Elateridae are also an interesting group, most notable for the ability of the adults to click themselves into the air when lying on their backs, due to a special notch and groove system below the head! This individual had a beautiful set of antennae in a lamellae, or plate-like, type structure.
Finally the Water Scorpions from the family Nepidae are a common sight in the bush, often found in our swimming pools and bird baths! The small sting like appendage at the back of this bug’s body is in fact a type of snorkel, used for breathing and it is totally harmless to us. These small predators hunt tadpoles and other insects in their aquatic environment, and are capable fliers, travelling from water source to water source.
How effective is Southern Cross’s Grey-water Filtering System?
Samantha Dold, Grade 12
Septic tank systems tend to pollute ground water; the French drains allow impure water to seep into the soil.
The grey water system at Southern Cross Schools filters the sewage from town, and the grey water (which includes dishwater, shower water and sewage) from the boarding house and from the college and prep school. This water enters a small, square dam (one on either side of the grey water dam) which is lined with clay. The water sits there for 30 days after which it is allowed into the grey water dam. Some of the grey water is pumped to irrigate the sports fields (which are by chance on higher ground so water seeps back into the system), and the rest flows out of the gabion situated at the dam wall into a stream which leads to Osprey Dam.
Overflow from the dam flows into the Sandspruit River, which then flows into the Blyde River. It is important to ensure that the water is adequately being filtrated as the Blyde River is an important source of water in the area both for people and wildlife.
Micro-organisms were added to the smaller dams to make the system aerobic, as opposed to a septic tank which is anaerobic, which helps to break down organic matter. Their main function is to turn sulphides (released by rotting organic matter) into oxygen.
Construction began in 2009, but was damaged and then rebuilt after the 2012 floods. Originally, the walls were too low and the dam was not big enough. It needs to be 1-1.5 m deep for organic processing to occur.
The purpose of this project was to determine how
effective Southern Cross’s Grey-water filtering system is - with the hypothesis being that the system efficiently filters the sewage water before it reaches Osprey Dam.
This was done by taking samples from a) the sewage stream, b) the Grey-water dam, and c) Osprey dam and testing the PH level, Phosphorous, Nitrate, Ammonium, COD levels, Coliforms and E.coli.
The dams are situated on the school property and Osprey dam is roughly 500 metres from the school.
The path that the water follows has been indicated in red in the above photograph. The location of the sample collections have been indicated by A and B on the photograph, C was collected at Osprey dam.
The graph above displays the parameters in which PH levels must fall to be safe. All of the samples collected clearly fall between these parameters. The PH level does slightly increase, leaning more toward alkaline in sample C. This is possibly due to the fact that with less waste product in the water, the acidity level decreases (as waste is acidic). This proves that the water is being filtered from sample A to C.
All three samples are well below the maximum limit. Sample B has a higher Nitrate level than sample A and C because the presence of Nitrate in freshwater is often due to the process of decomposition of waste. The waste is broken down specifically in the Grey water dam because micro-organisms were added to make the system aerobic (requires oxygen). The micro-organisms release nitrates during the oxidation process (decomposition).The higher levels of nitrate here, promote the growth of the creeping water primrose as nitrate encourages growth of aquatic plants. Nitrate is not harmful to aquatic life (fish, frogs etc.)
There is a clear decrease in Ammonium levels from the sewage stream to Osprey dam. High ammonia levels as indicated on the graph (maximum levels) may be harmful to aquatic life, but levels measured should not be of any harm. The presence of ammonia is due to the presence of sewage effluent, but is very clearly filtered out by the time it reaches Osprey dam, proving the efficiency of the Grey water system.
COD, (chemical oxygen demand) as explained in ‘reasons for substances tested’, is the amount of pollution that cannot be broken down biologically. The graph above illustrates extremely high pollution levels, Sample A in particular does not comply with safety limits set by department of water affairs.
cfu = colony forming units
i.e. single cells of the same organism
The high level of coliforms in sample A indicate the unsanitary quality of the water. There is no maximum limit as to the level that may be found in water. Clearly, the sanitary quality improves with each sample, proving the efficiency of the Grey-water system.
cfu= colony forming units
i.e. single cells of the same organism
E.coli is a harmful bacteria found in human waste. The levels are significantly reduced- to almost nothing, making the water in the Grey-water dam and Osprey dam clean enough to support aquatic life. This proves the efficiency of the Grey-water system.
As displayed on the graphs above, each of the levels of constituents decreased through the grey water system. (apart from Nitrate, which is explained in the note under the graph.)
Although Phosphorous is listed as a constituent, the levels were so low they were negligible.
PH level- acidity decreased by 7.2%
Ammonium level- decreased by 95%
COD level- decreased by 24%
Coliform level- decreased by 98 %
E.coli level- decreased by 99%
The water in the Grey-water dam, as well as Osprey dam is pure enough to support aquatic life. All of the constituents, on much higher levels, have the potential to be harmful to organisms, but the levels found in these dams are harmless.
Hypothesis proved - Southern Cross’s Grey-water filtering system is efficient!
More Camera Trap Images Revealed! - Byron Wright
In August a giraffe carcass was found and moved to the wilderness area along eastern fence and a camera trap was set up to record events. Over a period of three days the jackal and vultures were the main animals on the carcass. There were two jackals that had to work hard to compete with many vultures, often losing the battle! In some of the photos you can see the jackal standing on the carcass trying to keep the vultures at bay.
Interesting Sightings on the Estate
There have been a flurry of Aardvark sightings recently - always a treat to see; and leopards spotted on camera traps at night or in the very early hours of the morning.
This leopard photo was taken at 3am on 2 July at Guineafowl Dam. The camera trap was put on a dead tree at the back of the dam. Over a two week period impala, warthog, wildebeest, kudu, duicker, guinea fowl, zebra and this single leopard were spotted.
Rob Severin, RV240
This leopard photo was taken just before 1am on 11 August in the southern wilderness area just after the unexpected rain. Byron Wright
This busy aardvark was seen at the junction of Tawny and Snake eagle at 4.15pm on 17 July.
Kerri Tremeer, RV150
This large (the size of a big warthog!) aardvark was seen late afternoon in mid and late July happily digging just off our deck. Lawrence Morgan, RV283
"Do you think she will notice if I eat her plants?"
Les Blandy, RV125
Common Duiker Lawrence Morgan, RV283
Waterbuck herd photographed in the early morning during August at Osprey Dam.
Lawrence Morgan, RV283
This monitor was photographed along Bateleur road, it was basking in the sun nearly every morning whilst the road works were underway. Byron Wright
A White-bellied sunbird contrasting beautifully with the 'Red Hot Poker' flower.
Lawrence Morgan, RV283
For years now we have had a series of francolin families
visit us, and over the past 2 years a pair of Dark Chanting Goshawks hunt these birds around our home – they must have taken out at least 7 or 8 that we've seen so far.
This is the latest victim on August 29 – it was chased into a window and nailed straight away.
Michael Brooke, RV200
2 giraffe sparring at Osprey Dam in the early morning during August.
Lawrence Morgan, RV283
A great series of this giraffe browsing. Lawrence Morgan, RV283
A Final Word - Content for The Raptor
There seems to be the mistaken impression that we are flooded with photos, sightings & observations from residents... we are not! So please do send any interesting notes - with or without photos - through to us. Special thanks to Sam Dold from Southern Cross Schools for her article - a great addition to this issue; and as always to our regular stalwart contributors!