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massive blow to their long-term conservation .
Where possible , natural vegetation should be allowed to grow to increase the size of Renosterveld patches . Fence-lines should be allowed to be wild , creating a more suitable habitat for the nesting birds .
Fire management in Renosterveld is important . Renosterveld needs to be burnt at regular intervals . In areas where the larks live , burning should not take place during their peak nesting time from August to November .
What threats do the eggs and tiny birds face ?
In the nests we monitored , we found that only 14 % of the larks survived long enough to take flight . The rest were eaten by predators . Bird species that nest and breed on the ground often lose a high proportion of their nests to predators , but lark nests are very well concealed .
Figure 2 . A well-hidden Agulhas long-billed lark nest on the ground in endangered Renosterveld . Alan Lee / BirdLife South Africa
Figure 3 . The endangered Renosterveld where the lark makes its nest . Courtesy Sanjo Rose .
Many predators on the Agulhas Plain rely on their eyesight to locate nests , so this camouflage generally pays off . As soon as the chicks are mobile , but before they can fly , they leave the nest area to hide under small bushes nearby , which makes them even harder to spot .
The high rates at which this lark ’ s eggs are being eaten may be because the small Renosterveld patch sizes make it easier for predators to find the nests . However , more research is needed into this .
The larks are frequently seen foraging in agricultural fields and are a common bird species in the area . Even though they prefer the threatened Renosterveld as a nesting habitat , the small patches of Renosterveld that remain and the lark ’ s adaptation to nesting in fields seems to be keeping the population going .
What kind of conservation does the lark need ?
It is critical that all remaining patches of the unique Renosterveld are protected .
There may well be a threshold of the amount of natural Renosterveld below which the lark would not be able to persist .
Indeed , there are other endangered bird and animal species who depend on Renosterveld and are of even more concern to conservationists , such as the southern black korhaan , black harrier and Stanley ’ s bustard . These birds have far bigger distributions , but the Agulhas Plains are also their main habitat and losing more Renosterveld would be a
Larks are small songbirds , and so animals who prey on nests also prey on the adult birds . Therefore , if an adult bird chose to aggressively defend its nest by mobbing ( squawking or flying at predators to chase them away ), it might well be eaten itself . The larks may be choosing instead to incur a short-term loss of chicks or eggs .
Larks appear to live reasonably long – up to 13 years – so missing a nesting season but surviving another year might be a better strategy .
Nevertheless , evidence from videos at the nests showed that reptile predators such as snakes and tortoises provoked a strong mobbing response from larks .
Why this occurred is still unclear , and there is a lot about the predator dynamics in the Renosterveld that needs further investigation .
Sanjo Rose of HawkWatch International contributed to this interview .
Grassroots Vol 24 No 1 March 2024 12