AFRICAN BIRD A WEEK

You will often see this african bird with its fantastic and bright colors during your safari in Kenya, because it is found almost everywhere, from sea level to 2700 metres, in savanna, in thornbush and acacia arid areas, open woodland, lakeshore woodlands, gardens and cultivated fields.

It belongs to Sturnidae family, within Passeriformes order.

Adults have black head and their back, the upper part of the breast, wings and tail are iridescent. Iridescent colors are not produced by pigmentation, but they are an effect of keratin layers.  I will write another article soon just to talk about iridiscence in birds.

Superb starlings are primarly monogamous, but there is a breeding pair with helpers, majority of which are male offspring from previous brood. This is what is called cooperative breeders.

Helpers acquire food, help in building the nest, and tend to the nestlings, which increases the chicks’ survival rates.

And here comes a funny and interesting thing: a a study found that superb starling females cheat on their mates for the sake of their chicks and will mate also with subordinate males from within their social group when they need help to raise their chicks. 

Females trade sex for help, indeed!

But it’s not all. Females may also cheat with males outside their group if they feel their mates are too genetically similar to themselves. Mating with strangers increases their brood’s genetic diversity, even though they don’t receive additional help. For the time being, it is not known yet how females detect the genetic similarities between themselves and their mates, even if also other bird species seems to take similar mating strategies.

Usually, if a female bird (and sometimes if a human female!) is caught cheating, the partner punishes her by doing less work in raising the chicks, or in extreme cases, leaves her to raise the chicks on her own. But because superb starlings are cooperative breeders, females have more incentive to move away because even if she is caught cheating, she still may get help from other group members. In any case, superb starlings tend to stray much less often than other cooperative breeders, despite the dual potential benefits for females in seeking extra-pair mates. We can say, in short, that superb starling females are faithless, but not so much indeed (less than other bird species)!

This behaviour matches with another one: females often leave the group when young, while most males live their entire lives with their families and, therefore, are usually related to the chicks. By helping the chicks survive, they pass on familial genes. The result is like having their own chicks, that’s why they don’t have any problems to remain in the family group. The same thing happens, for example, with a mammal that lives in savannah: the jackal!

Sources: news.cornell.edu; wikipedia