Mangrove Robins hide behind my back

Braved mozzies and mud after Mangrove Robins (Peneonanthe pulverulenta) today. Found three, parents feeding nearly mature youngster. Never in two hours up close in front of camera. Three times right up close behind me - surrounded by low-growing mangroves. Above, distant shot of immature bird.

Here's probable parents pictured many weeks ago. In the interim failed to find nest, or, indeed, any hint of nesting.