The Secretary bird’s skull-crushing kick
Maja Mielke
Secretary birds stomp their prey to death with forces up to 5 times their body weight.
I was listening to one of my favorite podcasts the other day while on my way to work. The title of the episode was ‘The Bird with a Skull-Crushing Kick’ (linked at the end of this newsletter). Rachel, the host presenting the topic, said, ‘This bird should be known more.’ And after finishing the episode, I couldn’t agree more.
So here we go—let’s talk about the Secretary bird!
Secretary birds (Sagittarius serpentarius) are large birds of prey that cover up to 32 km a day on foot searching for prey in the sub-Saharan grasslands of Africa. These birds can fly, but they spend most of their time on the ground on their exceptionally long legs—which they use to stomp their prey to death with forces up to 5 times their body weight.
Allow me to introduce you to Madeleine. Madeleine was a male Secretary bird living at the Hawk Conservancy Trust in the UK. This bird was trained to aggressively kick a rubber snake to demonstrate his hunting strategy to the visiting public. In 2012, researchers came to measure the force of his kicks1 with a force plate that they placed under the rubber snake.
(You can watch Madeleine in action here.)
These measurements revealed a striking force of about 200 N, which equals the weight of about 20 kg—5 times the body weight of the bird. Madeleine stomping on the head of a snake thus had the same effect as dropping a 20 kg weight on the prey.
But the kicks of Secretary birds are not only forceful, they’re also exceptionally fast. The recorded impacts of Madeleine lasted only about 15 ms (1/67 of a second), making the strikes even more effective in knocking out prey. This is essential since these birds also feed on venomous snakes—one insufficient strike could be deadly.
These rapid movements are possible because of the Secretary bird’s extra-long legs, which make up about 50% of its standing height. No other bird of prey has such long legs.
Madeleine passed away in 2022 at the impressive age of 34 years (in the wild, these birds live only up to 15 years). He’s been a great ambassador bird for the species, helping us to better understand and appreciate the impressive skills of the (sadly endangered) Secretary bird.
Rachel ended her podcast episode with the words, “I’m falling a little bit in love with them because they are just so pretty.”
Nothing to add here.
PS: You can listen to the mentioned podcast episode here.
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