The Spotted Thick-knee
, Burhinus capensis
, is actually an omnivore. They will feed mainly on a range of insects and other invertebrates, small lizards, rodents, snails, crabs and even an occasional frog, but often grass seeds are included in their diet. The stomach contents hold substantial amounts of grit, small pieces of glass and metal.
The large yellow eyes are an adaptation to being active at dusk and dawn and at night. The bird’s long legs appear to have thick knees, hence the name “Thick-knee”. However, the actual part that looks like a thickened knee is not the knee but actually the heel of the foot.
This thick-knee likes dry, open country. Its brown, black and white colors blend well into its surroundings. The birds rely on their extremely effective camouflage to protect themselves from predators. The photograph below shows the thick-knee in typical day-time pose. They remain motionless like this until you are virtually on top of them and then will suddenly fly off, giving you a near heart attack.
Thick-knees are usually quiet birds during the daytime and quite noisy during the darker hours when they are active. They are capable of flying but would rather walk. They are very mellow and will only move from their spot if you approach very closely.
The males do become aggressive and territorial when they are protecting or defending the young. Spotted thick-knee is thought to have a long-term pair bond. They start breeding in August and the last chicks may only fledge in May. In addition, a pair may have more than one successful breeding attempt; some have been recorded rearing chicks successfully from four different nests during a season. If nests or chicks are lost, further attempts to breed may occur. They lay one to three speckled, brown eggs in a scrape in the sand, lined with vegetation. Nests are usually in the open under or near tall trees. The eggs take about a month to hatch and the chicks between five and six weeks to fledge. Both parents will help incubate the egg, though the mother tends to do most of the brooding. This species has a life span of 20 years, but have survived over 30 years in captivity.
They are regularly preyed upon by Verreaux’s and spotted eagle owls and tawny eagles.