Nesting Material and Nest Building Technique in Two Species of Broadbill (Cymbirhynchus macrorhynchos and Corydon sumatranus, Passeriformes, Eurylaimidae) from Southern Vietnam

Notes on nesting, territoriality and behaviour of broadbills (Eurylaimidae, Calyptomenidae) and pittas (Pittidae) in Tawau Hills Park, Sabah, Malaysian Borneo

“…Young individuals, identified by their paler, smaller throat patches and paler bills, were present and called loudly with the others (ML 471545-546). Although immatures did not actively participate in nest construction while we watched, their presence is consistent with suggestions that the species breeds cooperatively (Lambert & Woodcock 1996, Zubkova 2017.…”

“…By the time the chamber was well formed, the base of the nest consisted of a large wad of fibres curling from the sides of the nest inwards. The nestbuilding techniques described here are generally consistent with those reported for Black-and-red Cymbirhynchus macrorhynchos and Dusky Broadbills (Zubkova 2017).…”

“…Although other broadbills sometimes breed cooperatively (Phillipps 1970, Lambert & Woodcock 1996, Zubkova 2017, we never saw more than two Black-and-yellow Broadbills at or in the general vicinity of nests, except once when two females and an unmarked male briefly perched near an almost constructed nest belonging to a different (colour-marked) male. One of the females entered the nest for a few seconds, but all three birds departed shortly afterwards.…”

“…The birds generally took turns, bringing material one at a time, and added each piece of stick, vine, leaf or moss atop the growing pile, sometimes with a head-shaking motion similar to that used by Eurylaimus broadbills (see above). We observed the 'winding' behaviour described by Zubkova (2017), in which a flying bird latches the loose end of a fibre to the top of the nest, then spirals downwards while balanced on the side of the nest, to place the other end of the fibre near the base. However, we also frequently saw birds simply place a new piece of material atop the tangle of fibres (both behaviours visible in ML 471148).…”

“…We occasionally saw broadbills carry triangular green objects (probably leaves) into the nest chamber during incubation. Other broadbills often line their nests with green leaves (Wells 2007, Zubkova 2017, although Wells (2007) noted that a Black-and-yellow Broadbill nest he inspected lacked them. Once we caught an image on video that could be sexed, and it was the male holding the leaf (ML 471552; Fig.…”