The secretary bird, Sagittarius serpentarius, is a distinctive raptor native to the African continent. This large, terrestrial bird of prey is recognized by its long legs and a unique crest of black feathers on its head. It is classified within its own unique family, Sagittariidae. Secretary birds inhabit the open grasslands and savannas across sub-Saharan Africa.
Primary Prey
Secretary birds are known for preying on snakes, including highly venomous species such as cobras, mambas, and puff adders. While their snake-hunting prowess is notable, these reptiles make up a small portion of their diet, around one percent. Despite this, snakes can be a locally significant food source in certain areas. Secretary birds are not immune to snake venom, relying instead on precise hunting techniques to avoid envenomation.
Hunting Strategies
These birds are terrestrial hunters, stalking prey on the ground. Their long, powerful legs are suited for covering distances, with an average daily range of 20 to 32 kilometers in search of food. The most characteristic hunting method involves stomping on prey with swift, powerful kicks. These kicks can deliver a force up to five times the bird’s own body weight, or about 20 kilograms, aimed precisely at the head or neck to stun or kill the target.
Secretary birds also utilize their wings for balance during a chase or to appear larger, which can intimidate and flush out hidden prey from tall grasses. For smaller prey items, they may use their strong bills to pick them up. Once incapacitated, most prey is swallowed whole. Their ability to deliver rapid and accurate strikes contributes to their success in subduing dangerous animals.
Varied Diet
Beyond snakes, secretary birds are opportunistic predators with a diverse diet. About 87% of their diet consists of large arthropods such as locusts, grasshoppers, beetles, spiders, scorpions, millipedes, and crabs. They also consume small mammals, which make up about 3.9% of their diet, including rodents like mice and rats, as well as hares, hedgehogs, and mongooses.
Other prey items include lizards, amphibians like frogs, small tortoises, and chameleons. Small birds and their eggs account for about 1.8% of their diet. This broad prey base highlights their adaptability to different environmental conditions and seasonal changes in food sources.
Role in the Ecosystem
The dietary habits of the secretary bird contribute to the balance of their ecosystem. By preying on a wide array of animals, they help regulate the populations of rodents and various reptiles, including venomous snakes. This predation supports overall ecological health within their grassland and savanna habitats.
Their consumption of pests such as locusts and rats also provides a beneficial service to agricultural areas. The secretary bird’s presence and hunting activities contribute to maintaining the natural checks and balances within the food web.