White-browed Coucal

Centropus superciliosus

This is the common Coucal throughout the usual safari areas of Kenya and Northern Tanzania. The clear supercilium makes it easy to distinguish from the rarer and more restricted Senegal, Black and Blue-headed Coucals.
Birds of Kenya and Northern Tanzania says it "sun-bathes with drooped wings partly spread, the back and rump feathers erected", so that explans what it's doing here.