Dark-necked Tailorbird collecting floss

Lin Yangchen documented a male Dark-necked Tailorbird (Orthotomus atrogularis nitidus) collecting fruits of the lalang grass (Imperata cylindrical) for its nest (above; field of lalang bottom). These fruits provide the floss that is probably incorporated with other plant materials as nest lining – seen in the nest of the Common Tailorbird (Orthotomus sutorius) and the Olive-backed Sunbird (Cinnyris jugularis), where there is a distinct lining of floss.

As Yenchen writes: “He made several trips to and fro (until the stalk was almost stripped of the fruits) but seemed to come from different directions sometimes (left and right). I am speculating that these ‘detours’ may be a behavioural adaptation to evade enemies.

“As the stalk was very flimsy, he hovered for short moments while plucking the fruits. These abundant fluffy things could provide thermal insulation for the chicks and are possibly less expensive (per unit insulating capacity) for the parents than using their own down, although the cheapness is offset by the energetic expense incurred in flying around looking for it.

“The actual nest seemed to be only about 1m away in a bush (which makes the search flights less expensive), but I didn’t try to locate it, so that he and his beloved wife could enjoy their private lives together.”

Image of bird by Yangchen, that of lalang by YC.