Friday, December 18, 2009

Why is the neighbourhood so quiet now?

Have you ever wondered what it would be like when the people living in your neighbourhood, many of whom may be your close friends and/or relatives, start disappearing from the area without explanation, never to return? As naturally gregarious creatures, human beings seem to mostly prefer the proximity of other people and often depend on those around them for friendship, support, acknowledgement, love and, at times, a livelihood. It is therefore a fairly logical assumption that, should the above scenario become a reality, it would have a profound effect on anyone affected by such a phenomenon. Should such disappearances continue, it is very likely that the remaining people living in such an area will abandon it altogether to settle elsewhere where conditions are generally more favourable.

Imagine if some super-sleuth started to investigate the disappearances and found that they can be ascribed to several mass-killings of those around you, mainly for the sale of their body parts in the illegal trade? Now that is very likely to elicit a flood of media exposure, Hollywood will probably be lining up to do B-grade movie deals to make millions and it would be recorded in the annals of high-profile macabre incidents for posterity. Suffice it to say that, should the perpetrators ever be caught and brought to justice, that there will be little mercy shown and that the maximum sentence would be handed down. That is, of course, if humans were involved.

Now picture the following…

A pair of African White-backed Vultures Gyps africanus has been nesting in the savanna of northern Zululand for many years as part of a loose congregation of about 24 active nests, most of which occur within the relative safety of a proclaimed nature reserve. These birds are gregarious and several individuals often forage together and constantly watch each other for clues as to where good sources of food can be found. It is also very likely that, should a bird be fortunate enough to reach breeding age and conditions are favourable in their natal area, they would pair up and settle with their mate to breed within the same area they have fledged from. These groups of birds are also likely to have one or more favourite waterhole within close proximity to their nesting sites where they spend quite a bit of time to drink, bathe and socialize with other vultures. This can easily be compared to your local pub, where you and your mates often get together to catch up and have a few!

Back to the pair of nesting birds. Their nest is situated in the top of a Knob-thorn Acacia Acacia nigrescens, about 20m above the ground. Due to the height of the tree and its rough bark, sturdy branches and very thorny stems, the tree forms a safe and stable platform for the nest which they have built from sticks. The nest is out of reach of most terrestrial predators and has been instrumental in the pair successfully raising a single chick every year for the last 11 years. It also has quite a spectacular view of the surrounding savanna, a mountain range to the east and the small bay in the nearby dam which they and the other vultures use as the local “social club”.

A view from the nest of the pair of African White-backed Vultures

 From here, they also have visual contact with at least seven other vulture nests, including one that used to be occupied by the much rarer White-headed Vulture Aegypus occipitalis pair which they have encountered on a number of occasions at carcasses and the drinking/bathing spot. “Used to be occupied” is sadly the appropriate term for at least 5 of these nests as the pairs that made use of them seem to have disappeared over the last 3 breeding seasons or so. This includes the pair of White-headed Vultures. In some cases, the birds went missing during the breeding season, leaving their chicks to eventually starve in the nests. In one instance, only one bird of a pair disappeared, but the task of providing food for itself and the chick in the nest was too much to ask and the chick eventually starved anyway. This adult seems to have moved away from the area as it hasn’t been seen in the area for many months now. Most of the nests have since collapsed, but some of the really sturdy ones still sit proudly on top of the trees on which they were built, but now are stark reminders of a once thriving congregation of breeding vultures.

Many nests, like this one, are still intact but no longer in use

If you thought that the above scenario is just a figment of the imagination, I am sorry to disappoint you. During our annual vulture colour-marking initiative in southern Africa in October this year, I was fortunate to spend almost 2 weeks in northern Zululand working with staff from Ezemvelo KZN Wildlife (EKZNW) on three of their reserves to visit vulture nests with the aim of fitting rings and tags to nestlings to follow their dispersal and movements after they have fledged. Due to logistical hitches and inclement weather, efforts on two of the reserves amounted to little more than a frustrating wait for not much to happen. It was however fantastic to see the first decent rains of the season fall in the area and seeing the Mkhuze river come down in flood for the first time in several years was certainly rewarding.

Conditions however sufficiently improved toward the end of the trip to enable us to get to work and a team of 12 people, including a crew from Eskom with one of their cherry-picker trucks finally were able to move into an area close to the Swaziland-border to check on known nests and ring and tag any nestlings that were found. The use of an Eskom cherry-picker truck to access vulture nests was pioneered by the late James Wakelin from EKZNW who sadly died in a plane crash in Moçambique in 2008. The cherry-picker enables fieldworkers to be lifted up to nests to work on nestlings without having to use a climber that must scramble up the tree along vertical branches and thorny twigs to get to the nest. Sadly, we were not able to do any work at these sites in 2008 due to James’ passing.

The effort however ended in a frustrating and perplexing process of visiting known nesting sites only to find that the trees have either collapsed, nests have started to disintegrate or were just no longer in use. Out of the 24 known nesting sites visited, we found only four active nests in the area, one of which contained a tiny chick that must have resulted from either a very late start to the breeding attempt or the first attempt having failed early in the breeding cycle. All of the 24 sites were active over the last 5 years and to find only four of these still active this year certainly was a worrying discovery. Although some of these nests may have become defunct due to old age, the death of the nesting trees or storm damage, it is highly unlikely that this could have accounted for all of them, especially when so many disused nests were still found intact.

A tiny African White-backed Vulture nestling

The most likely factor that this decline in the breeding population of vultures in this area can be ascribed to is that a substantial number of adult breeding birds have been removed from the population by some or other means. Based on information obtained and incidents that have taken place over the last 3 years, it is very likely that most of the “missing” birds have been killed by feeding on poisoned carcasses placed in the veld for the explicit purpose of killing vultures. In 2007, 50+ vultures were killed during a mass-poisoning near the Mkhuze Game Reserve and earlier this year, another poisoning was reported from the area in which a substantial number of vultures were killed.

It is believed that these birds were killed to obtain their heads and feet for use in the traditional medicine trade as many of the vulture carcasses were found with the heads removed. The head is the most popular part of vulture carcasses that is used in the trade. Various agro-chemicals are readily available in this area, among others from the large-scale cultivation of sugarcane and other crops. EKZNW estimates that, should the current trend of vulture poisoning continue, that even common species such as African White-backed Vultures would become extinct in KwaZulu-Natal within the next 15 years. The current rate of decline in the breeding population of the above area certainly seems to support this prediction.

What can be done to address this? Trying to physically safeguard highly mobile birds like vultures from being poisoned is a near-impossible task. Not even the largest protected areas in Africa are large enough to achieve this and we know that vultures can cover several 100km² in a day in search of food of which a substantial part of its foraging range will fall outside of existing parks and reserves. It only requires one or two individuals within such an area with the intent to kill vultures to have a huge impact on the vulture population of an area. Poisoning is a highly effective, silent method which can be done randomly and anywhere and at its worst kill hundreds of birds at a time. Recent poisoning events in Tanzania where more than 300 birds in a single incident were killed once again confirm this.

This does not mean that we should give up on trying addressing the issue. A similar trend was noted in the 1960’s, 70’s and 80’s in South Africa which was fairly effectively countered by providing the public with important information in this regard to ensure that agricultural and other chemicals were better managed, controlled and used with due consideration of their potential impact on the environment. What is particularly relevant in this case is the fact that the use of poisoned vulture parts by people could potentially also lead to the death of the individuals concerned and this information should be made known to the potential clientele of dealers trading in vulture parts. The focus on the human-health issue is far more likely to have an effect in creating awareness of this threat in rural communities rather than trying to focus on the environmental impact. At the same time, it is essential that law enforcement with regard to the misuse of poisons is stepped up and that the penalties for people that are apprehended and found guilty of the misuse thereof, be appropriate to the potential impact of the crime on the environment and the community within which it took place.

Together with the loss of habitat, the threat of poisoning is currently by far the most serious that vulture populations in Africa face and it will take a continued and concerted effort by all parties concerned to effectively curb and address this.

Back to the pair with the small chick in northern Zululand…

I am happy to say that the small chick was successfully raised to fledging age by the parents and has finally left the nest a few days ago. Let’s hope and trust that our efforts in conserving these birds will assist to ensure that it will one day be able to return to this area with its mate to build a nest and breed in a revived congregation of breeding pairs. This neigbourhood can and must be revived.

It will take a lot of hard work and concerted effort to ensure that this fledgling returns
to its natal area to breed one day


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