Life in the Slow Lane: Reproductive Life History of the White-Browed Scrubwren, an Australian Endemic

An understanding of geographic and phylogenetic variation in passerine life histories is hampered by the scarcity of studies from the Southern Hemisphere. We documented the breeding biology of the White-browed Scrubwren (Sericornis frontalis), an Australia endemic in the Pardalotidae (parvorder Corvida). Like other members of the Pardalotidae, scrubwrens had a long laying interval (two days), a long incubation period (declining from 21 to 17 days through the season), and a long period of postfledging parental care (6 to 7 weeks). Scrubwrens appeared to be typical of the Australian Corvida in having a small clutch size (three eggs) and a long breeding season (5.4 months), and they also had a long interval between breeding attempts (10 days after a failed attempt, 21 days after a successful attempt). Scrubwrens were multibrooded, often raising two broods successfully and occasionally raising three broods. The breeding biology of scrubwrens adds further support to claims of a distinct life-history strategy for members of the Corvida but also reinforces evidence that some “Corvida” life-history traits more specifically are those of the Pardalotidae.