In South Africa, the distribution of the black harrier is distinctly polarised in both the Western and Southern coastal plains.

[3] Black harriers are migratory birds and their annual movements cover the southern half of the land surface of South Africa (including Lesotho) however, there is great individual variability.

Higher temperatures may also lead to poorer environmental conditions for breeding resulting in a decreased abundance of small mammals.

Whilst in coastal regions the proportion of small mammals in the diet increased with higher winter rainfall.

[5] The greatest number of breeding pairs can be found in the Western Cape province, South Africa.

[4] The black harrier population has declined in recent years to fewer than 1000 birds, and it is now considered endangered in South Africa, Lesotho and Namibia.

[4] This is due to the destruction of its original breeding habitat, South Africa's natural shrubland, the fynbos, which has been greatly reduced by encroaching cereal culture and urban expansion as well as the invasion of alien plant species.

The harriers in the montane environments are not as successful as those along the coastal strip which has fynbos, they breed poorly, take a wide range of prey and are subject to high levels of nest predation.

[3] This land transformation has therefore negatively effected the black harriers Carotenoids are pigments which are responsible for the yellow, orange and red coloration of traits such as the eye and plumages, displayed by many avian species.

Nestlings with a bird rich diet have higher levels of circulating carotenoids and display a greater carotenoud based colouration than those consuming more mammals.

DDT contaminated black harrier nestlings have significantly lower levels of circulating carotenoids and carotenoid-based coloration