Bird of the Year 2019 – Secretarybird – Hunting Factsheet 2
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BIRD OF THE YEAR 2019 HUNTING BEHAVIOUR & DIET WINGS EXTENDED FOR BALANCE Deadly Strike ANGLE HEAD TO SEE PREY WELL BEFORE STRIKING A team of scientists has studied the hunting technique of Secretarybirds BINOCULAR VISION FROM HIGH HEIGHT and discovered the birds can kick a TO SPOT PREY & MEASURE DISTANCE TO heck of a punch at 195 Newton. That PREY FOR ACCURATE STRIKE is the same as five times their own body weight! This is made even more HIGH LEVEL OF COORDINATION BETWEEN THE VISUAL, BRAIN & MUSCLES deadly with the extraordinary speed of the strike itself. The contact time STRIKE HAS TO BE FAST AND ACCURATE between the bird’s feet and the prey is WITH POISONOUS SNAKES OTHERWISE IT less than 1/10th of the time it takes to CAN BE DEADLY TO BIRD blink an eye. DEADLY STRIKE FROM A LEGS ARE TWICE AS LONG AS OTHER They also found the birds pre-plan the GROUND BIRDS OF SIMILAR BODY MASS STATIC STANDING POSITION strike and, once they kick, they cannot USING ONLY THE LEG MUSCLES PEAK FORCE OF STRIKE IS VERY HIGH change the direction of the strike & FAST TAKING LESS THAN 15 MS even if it is off-target. If they miss, they have to recalculate and do it KICKS AT SNAKES HEAD UNTIL IT IS DEAD again. Hunting Behaviour Prey of Choice Secretarybirds hunt on the ground, alone or in pairs, taking Secretarybirds have large gapes and steady long strides as they scan the long grass for movement swallow most small prey whole, so of prey. This can go on for hours in the heat of the day as their no time is lost tearing up prey which hunting territory is usually large, in some cases 20km2. This is they might lose to other piratical not a problem, as they are able to soar to cover large distances. species like Tawny Eagles or They will stomp on thick tuffs of grass or dung heaps to flush Bateleurs. Large prey is held down out prey. When prey is spotted, they quicken their pace to with their claws and torn up with achieve the element of surprise. Sometimes the birds will their bill. chase after it, flapping their wings untill they catch it. With large A study done in 1978 in Kruger National Park gives us a little prey, they will stomp down with their feet to kill the prey. With bit more insight as to what food the Secretarybird eats: snakes particularly, they will strike the snake behind the head, breaking its neck. Small prey is simply picked up with the bill, no ARTHROPODS stomping needed. Large prey is sometimes hidden under a (INSECTS, SPIDERS, bush for eating later. 87% BEETLES) HEAD DOWN, SCANNING THE GRASS FOR PREY LIZARDS WALKS 120 STEPS/MINUTE AT 2.5 - 3 KM/HOUR 3.9% RODENTS WALKS 20 - 30 KM/DAY 3.3% BIRDS GRASS < 0.5 M TALL OTHER 1.8% 1% (LIKE SNAKES) LONG LEGS & MODIFIED FEET ARE PERFECT FOR TAKING MEASURED STEPS ACROSS THE GRASSY LANDSCAPE COMPOSITION OF DIET IN PERCENTAGES Seasonal differences will affect what prey are available. Content and Illustrations: Chrissie Cloete @ChrissieCanDraw I Sources: Steyn, P. 1983. Birds of prey of southern Africa. Tanager Books, Dover NH. I Dean, WRJ, Ryan PG (eds) Roberts - Birds of Southern Africa (VIIth Ed) Cape Town: The Trustees of the John Voelcker Bird Book Fund. I Kemp M.I. and Kemp A.C. 1978. Bucorvusa and Safittarius: two modes of terrestrial predation. Proc. Symp. African Predatory Birds, pp. 13-16. Pretoria: Northern Transvaal Ornithological Society. I Steven J. Portugal, Campbell P. Murn, Emily L. Sparkes, and Monica A. Daley. The fast and forceful kicking strike of the secretary bird. Current Biology 26, R47–R59, January 25, 2016. .