Note to snakes: don’t be fooled by Secretarybirds’ seductive pink leggings. The explosive kick of Africa’s iconic bird has the force of 5 times its weight.
By Rex Graham
And the speed of their 15-millisecond stomps, or about one-tenth the time it takes to blink an eye, means you have no chance of biting back.
Researchers at the University of London who studied a 4-kg (8.8-lb) male Secretarybird named Madeleine said each kick involves rifle-like targeting and firing of individual clawed feet.
“They are using visual targeting and feed-forward motor control – pre-planned movements – during strike events,” Steve Portugal, a biologist at the university’s Royal Holloway, the Royal Veterinary College and the Hawk Conservancy Trust, said in the journal Current Biology. “This means the birds can only correct for a missed strike in the next kick – once they’ve started a kick, they can’t adapt it, and they have to wait for the next strike.”
National park regular
It equals the birdwatching appeal of the Bateleur, a black eagle with a scarlet face, and the Saddle-billed Stork. As one of the most revered birds of Africa’s grass savannas and dry steppes, the vulnerable Secretarybird is easiest to see in national parks and other protected areas. More intense agriculture and increase in the human population are pushing the birds off their ancestral ranges.
The Secretarybird is part of South Africa’s coat of arms and it is the national emblem of Sudan
Adam Riley, a nature photographer and owner of Rockjumper Birding Tours, has been admiring them for decades in Kenya, Tanzania, Uganda, Namibia, Botswana, Zambia, Mozambique and Riley’s home country of South Africa. Sub-Saharan Africa is a rich habitat for its favorite food – venomous and nonvenomous snakes.
Secretarybirds’ varied diet
In addition to eating snakes, Secretarybirds take grasshoppers and beetles when they are available. They also eat most small lizards, amphibians and mammals, swallowing them whole with the help of their wide gape. Domestic chickens are occasionally on the menu.
“With its dietary habits, it occupies a similar biological niche to the Roadrunners of North America and the Seriemas of South America,” Riley said.
In 1990, capture and export of the raptor was prohibited by members of CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora). However, agriculture and human settlements, especially in Kenya, have eliminated Secretarybirds from much of their former range.
Data from a citizen-science project called the Southern Africa Bird Atlas Project has documented the decline not only of Secretarybirds, but also of many other wildlife species.
“Initially, these projects were not designed within a robust ecological and statistical framework,” scientists at the South African National Biodiversity Institute and the University of Cape Town said in the journal Biological Conservation. “Increasingly, however, projects are designed around scientific protocols that strike a practical balance of rigour, ease, and fun.”
What gives in Kruger?
Unfortunately, the Bird Atlas Project documented recent steep declines of Secretarybirds in Kruger National Park, an ominous development for such an important biodiversity site. The picture is complicated by Secretarybirds’ penchant to wander widely in search of optimal foraging opportunities.
A study of 23 Secretarybird nests 1991-1993 in South Africa’s Kgalagadi Transfrontier Park recorded high fledging rates. Females usually lay 2-3 eggs per season. Researchers based at the Mkhunyane Reserve and South Africa’s Environment and Conservation Department said the fledging rate was 2.2 fledged young per nest, including 7 nests with 3 eggs each, all of which hatched and fledged chicks.
Low rain, no problem
In years with exceptionally low rainfall, the nomadic Secretarybirds sometimes abandon Kgalagadi Transfrontier Park.
The researchers noted in a report in the journal Ostrich that in 1988 and 1989, when the nests were actually built, were periods of above average rainfall. To complicate matters, Secretarybirds increased in the Kgalagadi Transfrontier Park in 1993, a very dry year.
“Rainfall alone may not be useful when looked at in isolation in relation to the population fluctuations,” the researchers said in Ostrich. “Environmental factors prevailing elsewhere in Africa at that time may have been responsible for these results. Also, Secretarybirds feed on insects such as locusts, which emerge after rains.”