13

2.5.5 Determination of monitoring effort

Two factors were considered in determining the monitoring effort for this programme: the facility size (in hectares and

turbine number); and the avifaunal sensitivity of the site. In addition to the guidance offered in Jenkins et al (2012),

members of the Birds and Wind Energy Specialist Group (BAWESG) have informally arrived at a ‘best practice’ of 12

hours of observation per Vantage Point (VP) per site visit. The current project exceeded this standard by collecting 16

hours of data at each VP on each site visit. The guidelines are not prescriptive in terms of how many Vehicle Based or

Walked Transects should be done on a site, but it is believed that the current complement covers this site adequately.

2.6 Sampling activities

At this site, since the primary concern is overflying birds (i.e. collision with turbines) and not birds displaced on site

(since the site is already highly transformed), the sampling of small terrestrial species has been excluded from the

programme and replaced with additional monitoring effort at the Vantage Points, explained in Section 2.5.5.

2.6.1 Counts of large terrestrial species and raptors

The aim of this data collection method is to determine as close as possible to how many individuals of each species are

present in a given area. Large terrestrial bird species and raptors are relatively easily detected from a vehicle, hence

vehicle based (VB) counts were conducted in order to determine the number of birds of relevant species in the study

area. Detection of these large species is less dependent on their activity levels and calls, so these counts could be done

later in the day. One VB was established (Figure 1), totalling approximately 28.4 kilometres. For more detail on exact

methods of conducting Vehicle Based transects see Jenkins et al (2012).

2.6.2 Focal site surveys and monitoring

Two Focal Sites were initially identified for this project, with a third being added after the first site visit. These consist

of the Enseleni Nature Reserve, specifically the open water (FS1 at 28 41 317S – 31 00 016E), Lake Mzingazi (FS2 28 45

52.5S - 32 4 51.5E) and the Richards Bay harbour area (FS3 - 28 46 134S - 32 04 836E). The Enseleni Nature Reserve

was chosen as a Focal Site due to it being an important refuge of natural riverine vegetation in the broader area. It is

approximately 6 kilometres from the nearest proposed turbines, but is linked via the Enseleni River to the site, and its

distance from the site should not be taken as an indication of low relevance to avifauna on site. Focal Sites 2 and 3 (14

and 16 kilometres straight line distance from the nearest turbine position respectively) were selected to allow

correlation with on-site data if necessary in the final analysis. For example if abundance of water associated species

such as flamingos and pelicans is low on the WEF site throughout monitoring but has also been low in surrounding

focal sites then it may just be a function of conditions during this period. Alternatively if abundance is low on site but

high in surrounding areas we have greater confidence in saying that these species do not use the WEF site frequently.

Focal Sites were monitored by visiting the site and scanning the site with binoculars from a suitable viewing point in

order to count which species and how many individuals are at the site.

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2.6.3 Incidental observations

This monitoring programme comprised a significant amount of field time on site by the observers. Much of this time is

spent driving between activities. As such it is important to record any other relevant information whilst on site. All

other incidental sightings of priority species (and particularly those suggestive of breeding or important feeding or

roosting sites or flight paths) within the broader study area were carefully plotted and documented.

The above efforts in ‘2.6.1’ to ‘2.6.3’ allow us to arrive at an estimate of the abundance or density of the relevant

species on site. This allows the identification of any displacement and disturbance effects on these species post

construction. However in evaluating the likelihood of these species colliding with turbine blades, their abundance is

not sufficient. We also need to understand their flight behaviour. It is the flight behaviour which theoretically

determines their exposure to collision risk. A bird which seldom flies, or typically flies lower than blade height is at

lower risk than a frequent flier that typically flies at blade height. In order to gather baseline data on this aspect, direct

observations of bird flight behaviour were required. This was the most time consuming and possibly the most

important activity to be conducted on site, and is elaborated on below.

2.6.4 Direct observation of bird movements

The aim of direct observation is to quantify bird usage of the study area over time; and to record bird behaviour which

may help explain any future interactions between birds and the WEF. Direct observation was conducted through

counts at two VP’s identified (Figure 1), to provide coverage of a reasonable and representative proportion of the

entire study area (total coverage being unnecessary and impractical given resource constraints). VP’s were identified

using GIS (Geographic Information Systems), and then fine-tuned during the project setup, based on access and other

information. Since these VP’s aim at capturing both usage and behavioural data, they were positioned mostly on high

ground to maximise visibility. The survey radius for VP counts is 2 kilometres. VP counts were conducted by two

observers, seated at the VP and taking care not to make their presence so obvious so as to affect bird behaviour. Birds

were recorded in a 180 degree arc in front of observers, although particularly interesting observations behind

observers were recorded separately where necessary, taking care not to compromise the quality of data obtained in

the frontal 180 degrees. In most cases the view shed towards the majority of proposed turbine positions was

prioritised. Data should be collected during representative conditions, so the sessions were spread throughout the

day, with each VP being counted over ‘early to mid-morning’, ‘mid to late morning’, ‘early to mid-afternoon’, and ‘mid-

afternoon to evening’. Each session was 4 hours long, resulting in a total of 16 hours of observation being conducted

at each vantage point on each site visit. Four hours is believed to be towards the upper limit of observer concentration

span, whilst also maximising the duration of data capture relative to travel time required to access the VP’s. A

maximum of two VP sessions were conducted per day, to avoid observer fatigue compromising data quality. For more

detail on the exact criteria recorded for each flying bird observed, see Jenkins et al (2012). The usage data collected in

this manner has been used to gain a better understanding of collision risk.

One of the most important attributes of any bird flight event is its height above ground, since this will determine its

risk of collision with turbine blades. Since it is possible that the turbine model (and hence the exact height of the rotor

swept zone) could still change on this project, actual flight height was estimated rather than assigning flight height to

broad bands (such as proposed by Jenkins et al 2012). This ‘raw’ data will allow flexibility in assigning flight records to

classes later on depending on final turbine specifications.

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2.7 Data management and analysis

2.7.1 Data management

Whilst on site, observers captured data onto paper datasheets. This was then captured electronically each night into

Microsoft Excel spreadsheets. Spatial data (flight paths drawn on paper maps) was then digitised by the specialist once

these hard copy datasheets were received via courier. Electronic data was emailed to the specialist and hard copy data

couriered at the end of the site visit. In this way, data is kept in both hard and soft copy version as a backup against any

mishap.

2.7.2 Data analysis

The data emanating from the walked transects, vehicle based transects, focal sites and incidental observations are

presented in simple tabular format by this report. Until post construction data becomes available and testing for

effects can be done, more elaborate analysis is not considered informative.

Bird flight and weather factors

The bird flight data is analysed statistically relative to the environmental factors as follows:

The environmental factor measurements (Temperature, Wind Direction and Wind Strength) were made available each

ten minutes over the survey time. Temperature, Wind Direction and Wind Strength are all measured quantitatively: °C,

degrees clockwise from North and metre/second respectively. These data were categorised since categorisation allows

a good general way to determine the associations that may exist between the bird counts and the environmental

factors. The categorisations were done as follows:

Temperature into classes Cold (<= 10°C), Mild (> 10°C and <= 20°C), Warm (> 20°C and <= 30°C) and Hot (>

30°C). The temperatures obtained from the mast were matched with the start time of each observed flight.

The average temperature of all records for a given class (‘aerials’, ‘others’ or individual species) in any watch

period is taken to be the temperature for the watch period for that class. Categorisation was applied to these

watch period average temperatures.

Wind Direction has the categories of the wind rose: N, NW, W, SW, S, SE, E and NE. Note that it has been taken

that the wind directions have been measured clockwise from North, i.e. North itself is taken to be 0° (or

360°), East at 90°, South at 180° and West at 270°. Watch period wind directions were computed in a way

corresponding to those of temperature. Wind direction measurements belong to a type that is known as

circular data and ordinary averages for circular data are not valid (for example an angle of 359° and one of 1°

have a “true” average of 0° but the usual average presents a result of 180°. The average values for wind

direction are therefore not listed: those in the database vary to such an extent that even the circular average

is misleading: the lengths of the resultant directional vectors are close to zero for both Aerial and Other birds

(meaning that the directions are spread around the unit circle).

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Wind Strength was categorised according to the Beaufort scale into Calm, Light Air, Light Breeze, Gentle

Breeze, Moderate Breeze, Fresh Breeze, Strong Breeze and Near Gale, Gale and Gale plus. Watch period wind

strengths were computed in a way corresponding to those of temperature.

The hypothesis of No Association over the categories of the environmental variable was tested by comparing the

observed and expected counts by means of Pearson’s Chi-square test (cf. Agresti, A., 2002). If these disagree to a

significant extent (the significance being measured by the p-value of the Chi-square statistic) it may be concluded that

preferences for a specific category or categories do exist. Values of the p-value less than 5% imply rejection of the No

Association hypothesis at the 5% level of significance. Under certain circumstances, usually when a given proportion of

the expected values in some categories are too small, the assumptions under which the distribution of the chi-square

statistic is derived are violated and the p-value becomes invalid. In such cases special software is required to compute

the exact p-value. Where required the exact p-values for the chi-square statistic have been computed, using the

software package StatXact 9 (cf. Mehta & Patel, 2010). Note that when the exact exceedance probability is computed

the degrees of freedom plays no role and is indicated as “not applicable”.

Bird flight – spatial analysis

The spatial analysis of bird flight data was conducted as follows: A Viewshed Analysis of the 2 kilometre radius around

each Vantage Point was undertaken to identify the areas that can actually be seen by the observers from the Vantage

Point. This was done by using 20 metre contours to create a Triangular Irregular Network. Birds in flight above the

ground surface can often be seen despite the ground itself not being visible. In order to account for this a point 30

metres above the ground was used, to correspond with the lower edge of the rotor zone. The final viewshed then

includes areas where birds 30 metres and higher above the ground could be seen. Only data from areas deemed visible

were displayed in the final figures. The recorded flight paths within this viewshed were vectorized to create lines for

each flight record. A 50 x 50 metre grid was created of the study area, which covers a two kilometre radius from the

observation point. The number of times a recorded flight path intersected a grid cell was calculated. The number of

observations per grid cell was categorised and each 50 x 50 metre grid cell is shaded in a colour to represent the

number of bird flights recorded through that cell. Six classes were used, representing: 0; 1-2; 3-4; 5-6; 7-8; and 9+ flight

records each.

3. RESULTS & DISCUSSION

3.1 Preparatory analysis

3.1.1 Definition of impact zone

As described by the scoping phase avifaunal study (Smallie 2012), this site was initially considered potentially sensitive

for avifauna due to macro or landscape scale features, including the Richards Bay harbour and surrounding pan and

lake system, and the Enseleni River system. As such, ideally the impact zone would really encompass these features.

Many of the species associated with the water at Richards Bay are all far ranging species. Whilst it is not considered

practical to monitor all of these features, the Richards Bay, Enseleni Nature Reserve and Lake Mzingazi areas were

identified as focal sites and visited during each site visit to determine which species were there.

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3.1.2 Description of study area

The following description of the vegetation on the site focuses on the vegetation structure and not species

composition since it is widely accepted within ornithological circles that vegetation is most important in determining

which bird species will occur there. The classification of vegetation types below is from Mucina & Rutherford (2006).

Figure 2. Vegetation classification (Mucina & Rutherford, 2006) for the Richards Bay Wind Energy Facility.

The site is split evenly between “Zululand Coastal Thornveld” in the northern inland areas and “Maputaland Coastal

Belt” in the southern areas. Field work revealed though that very little natural vegetation remains on site. The area

has largely been transformed for the cultivation of sugar cane. Small patches of natural vegetation remain in the

drainage lines and on ground that is too steep for cultivation. The significant amount of transformation of natural

vegetation for agriculture means that the below description of micro habitats is far more informative than the

vegetation description.

More detail than is provided by vegetation classification is required in order to understand exactly where within the

study area certain species will occur and how suitable these areas are for the relevant species. The habitats available

to birds at a small spatial scale are known as micro habitats. These micro habitats are formed by a combination of

factors such as vegetation, land use, anthropogenic factors, topography and others. The following micro habitats were

identified during this programme (relevant bird species likely to make use of each micro habitat are shown in Table 1):

Rivers and drainage lines: Several small drainage lines and streams bisect the study area, such as the Okula River. To

the east lies a significant river, the Nseleni. These systems are important as they have a different vegetation

composition to the remainder of the study area and represent an important flight path for many bird species, and the

Nseleni River has significant open water areas which are attractive to birds. Since so much of the site is transformed,

these rivers assume even greater importance for certain bird species as refuges and ecological corridors.

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Dams: Many thousands of earthen and other dams exist in the southern African landscape and have altered flow

patterns of streams and rivers. Whilst damming up rivers has been a detrimental effect for certain bird species through

flooding their natural habitat, a number of species have benefited from their construction. The construction of these

dams has probably resulted in a range expansion for many water bird species that were formerly restricted to areas of

higher rainfall. These include species such as the pelicans, darters and cormorants and many other waterfowl. Several

small dams, and one large dam are present on and adjacent to the site. At the large dam on this site, Woolly-necked

Storks, and African Fish Eagle (seen multiple times) are two significant species observed to be utilising the area. These

species would probably not frequent this site if this dam were not present.

Thornveld or woodland: The woodland biome covers most of the northern and eastern parts of southern Africa and is

defined as having a grassy under-storey and a woody upper-storey of trees and shrubs. Woodland can be divided into

two types: the fine leaved arid, often Acacia dominated woodlands in the drier parts of the country, and the

predominantly broadleaved woodlands in the wetter regions such as this site. The woodland bird community is the

most species rich community in southern Africa. Complex differences in bird species distribution and abundance are

seen between the different woodland types. In this study area woodland remains only in drainage lines and on the few

steep slopes and does not play a major part in determining bird presence or abundance on site.

Arable or cultivated land: These areas can represent significant feeding areas for many bird species in any landscape

for the following reasons: through opening up the soil surface, land preparation makes many insects, seeds, bulbs and

other food sources suddenly accessible to birds and other predators; the crop or pasture plants cultivated are often

eaten themselves by birds, or attract insects which are in turn eaten by birds; during the dry season arable lands often

represent the only green or attractive food sources in an otherwise dry landscape. However, the crop planted has a

major effect on the attractiveness to birds, and the sugar cane that dominates this site is an extremely unattractive

micro habitat for birds, particularly when mature. The one minor exception to this is when the crop is just planted and

there is still bare ground, during which time certain birds may frequent the area to forage. Bare ground also allows for

greater heating up of the air above it, resulting in thermals which are utilized by various bird species, such as raptors

and storks.

Ridges: Ridges represent important habitat for a number of species due to their favourable air currents. Most relevant

to this study are the aerial species such as raptors and swifts/swallows – which favour flying along ridges where there

is ‘ridge lift’ (or orographic lift). Wind that is perpendicular to the ridge line is forced upwards when it meets the ridge,

thereby creating lift, long continuous ridges resulting in greater lift. In addition, the air is heated differently by the sun

on either side of a ridge, resulting in thermal lift. Birds use this lift to gain altitude, forage or move between locations –

all with less effort than would be required elsewhere. Larger soaring species such as storks and vultures will also circle

over ridges as they gain height and exploit the conditions. On the lee side of the ridge, several ‘waves’ may form.

Whilst these waves can potentially also favour bird flight, it is probably more likely that the turbulence in this area

would be detrimental to birds and probably avoided, particularly by smaller species. Various studies internationally

have found higher wind turbine bird mortality rates close to steep ground (including Orloff & Flannery 1992; Howell &

Noone, 1992; Thelander & Rugge, 2001). The increased wind speed in these ridge areas may also mean that birds

have less control of their own flight and are less able to adjust to avoid obstacles such as wind turbines. There is a

minor ridge line running through the site, and it is also one of the few remaining areas with natural vegetation.

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Exotic trees: Plantations of exotic trees often provide roosting and nesting substrate for various bird species, and as

such their importance for avifauna should not be underestimated. Several such stands of trees exist in the study area

and could provide refuge for amongst other species: Black Sparrowhawk Accipiter melanoleucus, Rufous-chested

Sparrowhawk Accipiter rufiventris, Long-crested Eagle Lophaetus occipitalis and Forest Buzzard Buteo trizonatus.

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a. Plantation area on site – Eucalyptus trees

b. Nseleni River, in the nature reserve at the N2

crossing

c. Upper reaches of the Nseleni River, in the north-east

of the site

d. Recently planted sugar cane lands

e. The large dam on site

f. Part of the ridge line on site

g. Mature sugar cane crop on the site h. Natural woodland on site, on the ridge line

Figure 3. Examples of the micro habitats available to birds on the Richards Bay Wind Energy Facility site.

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3.1.3 Development of the target species list

The national list of priority species compiled for the sensitivity map (described above – Retief et al, 2011) comprises

105 species, at least 46 of which could occur on the Richards Bay site (Harrison et al, 1997). Taking this and various

other sources into account a shortlist of 31 bird species was identified as final target species for Richards Bay (see

Table 1).

Table 1. The final target bird species for the Richards Bay project, and each species’ preferred micro habitats on the

Richards Bay Wind Energy Facility site.

Common name Species name Conservation

status

Suitable micro habitat on site

Saddle-billed Stork Ephippiorhynchus senegalensis E Enseleni River, large dam

Woolly-necked Stork Ciconia episcopus NT Enseleni River, large dam

African Openbill Anastomus lamelligerus NT Enseleni River, large dam

Yellow-billed Stork Mycteria ibis NT Enseleni River, large dam

Black Stork Ciconia nigra NT Enseleni River, large dam

White Stork Ciconia ciconia Bonn Almost anywhere, but mostly

Enseleni River, large dam

Greater Flamingo Phoenicopterus ruber NT Large dam

Lesser Flamingo Phoenicopterus minor NT Large dam

Great White Pelican Pelecanus onocrotalus NT Large dam

Pink-backed Pelican Pelecanus rufescens V Large dam

Hamerkop Scopus umbretta - Enseleni River, all dams,

drainage lines

Black-bellied Bustard Lissotis melanogaster NT Woodland

African Crowned Eagle Stephanoaetus coronatus NT Woodland

African Fish-Eagle Haliaeetus vocifer - Enseleni River, large dam

African Marsh-Harrier Circus ranivorus V Arable land

White-backed Vulture Gyps africanus V Woodland, almost anywhere

Brown Snake-Eagle Circaetus cinereus - Woodland

Black-chested Snake-Eagle Circaetus pectoralis - Woodland

Southern Banded Snake-Eagle Circaetus fasciolatus - Woodland

African Harrier-Hawk Polyboroides typus - Woodland

Ayres Hawk-Eagle Aquila ayresii - Woodland

African Hawk-Eagle Aquila spilogaster - Woodland

Black-shouldered Kite Elanus caeruleus - Woodland, arable land

Booted Eagle Aquila pennatus - Woodland

Jackal Buzzard Buteo rufofuscus - Woodland

Lanner Falcon Falco biarmicus - Woodland

Amur Falcon Falco amurensis - Woodland

Long-crested Eagle Lophaetus occipitalis - Woodland, exotic plantations

Spotted Eagle Owl Bubo africanus - Woodland

Steppe Buzzard Buteo vulpinus - Anywhere

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Yellow-billed Kite Milvus parasitus - Anywhere, mostly arable lands

E = Endangered; V = Vulnerable; NT = Near-threatened; Bonn = Protected Internationally under the Bonn Convention

on Migratory Species; - = no conservation status

In addition to the list of target species, the micro habitat that each species is most likely to be found in on the site (if it

occurs on site) is also shown in Table 1. Since birds are highly mobile, they can occur anywhere at any given time, but

most species do prefer certain types of micro habitats, and these are the areas where we would expect to find them

most of the time. These are also therefore the areas where impacts are most likely to occur. The raptors in particular

range widely and can soar over almost any habitat in search of food.

Based on the findings of this programme it is evident that many of the species identified initially as target species in

fact do not utilise this site and are not target species. This is elaborated on more elsewhere in this report.

3.2 Sampling activities (Objective 1)

3.2.1 Counts of large terrestrial species and raptors

The results of the vehicle based count (VB1) are summarised in Table 2 (expressed as birds per kilometre of transect).

This data collection did not capture very much data at all. This is probably a result of the low incidence of large

terrestrial species in the area (since the habitat is largely transformed) and the relatively poor visibility from a vehicle

in this terrain. The data arising from the Vantage Point counts described elsewhere in this report demonstrates that

the large raptors one would normally expect to record with vehicle transects do in fact visit the site. This illustrates the

importance of a monitoring programme consisting of multiple data collection methods. The species with the highest

index was the Woolly-necked Stork, with 0.18 and 0.11 birds/km in autumn and spring respectively.

Table 2. Species recorded during the vehicle based transect across the four seasons. Abundance of each species is

expressed as number of birds per kilometre of transect, with the number of records for that species shown in brackets.

Species Conservation

status Autumn Winter Spring Summer

Martial Eagle V 0.04 (1) 0 0 0

Woolly-necked Stork NT 0.18 (1) 0 0.11 (2) 0

Black-shouldered Kite - 0.07 (1) 0 0 0

Spur-winged Goose - 0.04 (1) 0 0 0

African Darter - 0.04 (1) 0 0 0

White-breasted Cormorant - 0.04 (1) 0 0 0

Rock Kestrel - 0 0.04 (1) 0 0

Yellow-billed Kite - 0 0 0.04 (1) 0

E = Endangered; V = Vulnerable; NT = Near-threatened; Bonn = Protected Internationally under the Bonn Convention

on Migratory Species; - = no conservation status

The location of each of these bird sightings is shown in Figure 4.

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Figure 4. Locations of all sightings of target species on the vehicle based transect. Blue dots denote sightings, each

labelled with an abbreviated species name (ME = Martial Eagle; RK = Rock Kestrel; BsK = Black-shouldered Kite; WbC =

White-breasted Cormorant; AD = African Darter; SG = Spur-winged Goose; WnS = Woolly-necked Stork, YbK = Yellow-

billed Kite). Black dots denote turbine positions.

3.2.2 Focal Site surveys and monitoring

The aim with Focal Site surveys is more qualitative than quantitative data collection. The results are therefore largely

anecdotal. A summary of the bird species recorded at each Focal Site is shown in Table 3. During the winter count, a

new Focal Site, FS3, was created at 28 47 876S: 32 04 052E in the Richards Bay harbour area. It is important to note

that both this focal site and Focal site 2 are well away from the Richards Bay site (approximately 14 and 16 kilometres

respectively) and were monitored as a reference against which bird data collected on site could be compared.

Table 3. Summary of bird species recorded at each of the three Focal Sites throughout the year. Note that Focal Site 3

is not on the proposed WEF site and is used for reference purposes. This data represents number of individual birds

recorded at the Focal Site in each case, irrespective of whether flying or not.

Species

Conservation

status Focal Site 1

Focal Site

2 Focal Site 3

African Fish-Eagle - 4 2 2

Woolly-necked Stork NT

2 4

Reed Cormorant -

4

Green-backed Heron -

2

Long-crested Eagle - 2

Barn Owl - 1

African Darter - 1

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Black Sparrowhawk - 3 1

Spur-winged Goose - 1

Egyptian Goose - 1

Hadeda Ibis - 1 1

Yellow-billed Kite - 2 1 3

Osprey -

1 4

Palm-nut Vulture

1

Goliath Heron -

1

Common Whimbrel -

7

Swift Tern -

7

E = Endangered; V = Vulnerable; NT = Near-threatened; Bonn = Protected Internationally under the Bonn Convention

on Migratory Species; - = no conservation status

Unfortunately access to the harbour area proved problematic on certain site visits and the full site was not always

adequately sampled. In order to get a better sense of bird abundance at this site, the CWAC (Co-ordinated Water Bird

Count project – www.cwac.adu.org.za) data was consulted for the Richards Bay site – SA079. Unfortunately this site

does not seem to have been counted since 2008. During the periods for which counts were available, far larger

numbers of birds, in particular waders, were recorded than by this monitoring programme. Larger species such as

pelicans did however not seem abundant. It appears that this data collection at off-site focal sites has not been

adequate to facilitate reliable correlations with the WEF itself. If this monitoring continues this aspect will require a

different approach, perhaps one of providing financial support to already existing bird monitoring programmes (such

as the CWAC) rather than trying to incorporate it into the on-site monitoring. At this end of the monitoring programme

this author is of the opinion that the likelihood of birds from Richards Bay commuting regularly across the WEF site is

lower than previously believed, and hence this off site data collection is probably also less important.

In general bird numbers at these focal sites were not particularly high.

3.2.3 Incidental observations

Similarly to the Focal Site surveys, the Incidental Observations result in primarily anecdotal information. Since most

incidental sightings are typically made whilst driving around the site in between other data collection activities, this

data is relatively sparse as with the vehicle based transects.