November at Londolozi is an exciting time of the year. Some of the more noticeable highlights include the first summer rain storms, the return of migratory birds such as the woodland kingfisher and the sudden arrival of hundreds of new-born impala lambs.
The impala lambing season seems to represent the official start of summer. In a matter of weeks the many impala herds dotted around the reserve almost double in size – and that’s no coincidence. Impalas are by far the most prevalent antelope species at Londolozi and that is partly due to their breeding strategy. I decided to read up on the matter and highlight everything you need to know about their lambing season and how it influences the behaviour of other animals, especially the predators.
The thing that initially caught my interest about the seemingly ubiquitous impala is the question: what exactly makes them so successful?
Part of the the reason why impalas dominate the landscape here is that their birthing strategy ensures a relatively large proportion of them go on to survive to adulthood. It is estimated that roughly 50% of impala lambs will survive their first year, which is impressive considering how vulnerable antelope in particular are during their first year of life. Once the impalas have survived their first year, their chance of making it through to an age where they are then able to reproduce increases significantly. With a strategy like this, it’s no surprise to learn that impala population has grown more than any other species in the Kruger National Park area.
There are many predators that attempt to capitalise on the weak and inexperienced newcomers to the wild world. Impalas combat the pressure from the predators by essentially flooding the market with young, and there are simply too many lambs running around for the predators to catch them all.
Within a period of about 3 to 5 weeks almost 90% of all impala lambs will be born, meaning that although many will succumb to predators, at least half of them will have enough time to grow strong enough and streetwise enough to evade predators.
While the impalas do have a brilliant natural solution to ensure their population’s breeding success, predators too make use of this time of plenty to advance their own agendas.
From the usual suspects like leopards and African wild dogs to less likely candidates like hyenas and martial eagles, many different predator species adapt their hunting style to make use of the many impala lambs around. Since it takes about two days for a newborn impala to be properly comfortable on its feet, the young impalas usually lie hidden in a thick area while their mothers are off feeding. Hyenas – who in this part of Africa usually only hunt around 30% of the time, if that – will actively go in search of newborn lambs. Thus it is not uncommon to see impalas looking particularly uneasy when hyenas are around come November, whilst at other times of the year the impalas almost completely ignore the passing scavengers.
Martial eagles are the largest we find at Londolozi and even they have a fondness for impala lambs, swooping down from the air to ambush their unsuspecting quarry. The smaller Tawny eagles and bateleurs will be found feeding on the afterbirth left behind once the lambs have been born – nothing goes to waste.
While it may seem cruel to talk about how predators exploit an abundance of impala lambs, it is part of the circle of life here in the wild African bush. Some solace we can take away from this situation is that due to the ingenious seasonal flood of young impalas, both the predators and the impalas of Londolozi somehow manage to come away from the situation flourishing.
Only nature can be that innovative!