Published in HBW Volume 14 on page 301.
Original HBW caption:

All members of a cooperative breeding group, parents and helpers, take part in defending the nest. When the nest is exposed to the sun, parents and helpers may also stay behind after delivering food, and shade the young with their wings. But despite the contributions of helpers, fewer than half of the studied nests of Dusky Woodswallows and Black-faced Woodswallows (Artamus cinereus) succeeded in producing fledged young, and groups of Black-faced produced a mean of just 1·5 fledglings per year. The problems begin with woodswallows’ exposed, flimsy nests. Those of the Black-faced, for example, are often unlined, and so sparsely woven that the eggs are visible from below. Several of the nests in the study were unseated by winds and storms, tipping out the eggs or nestlings. No nest predators were identified, although the two studied species mobbed potential predators like falcons (Falco), kookaburras (Dacelo) and ravens (Corvus) aggressively. The Pallid Cuckoo (Cuculus pallidus) has been recorded as an occasional parasite of Masked (A. personatus), White-breasted (A. leucorynchus), Dusky and Black-faced Woodswallows. No information is available on the breeding success of other woodswallow species.