Phylloscopidae Leaf Warblers
Version: 1.0 — Published March 4, 2020
Introduction
This family, recently split from the once enormous Sylviidae, contains a number of very small songbirds that forage with restless motion on or just above branches and leaves for small insects, often flicking their wings and using their fine, thin bills combined with rapid hops and hovers to capture their prey. Most have fairly unprepossessing plumage: olive backs, yellow to light gray undersides, and very often some wing bars and a striped or chestnut crown. Their songs, like their plumage, tend to be fairly simple—largely a jumble of thin warbles, buzzes, or repeated syllables. Though they spend most of their time foraging in tree crowns, they generally place their nests low, near, or even on the ground.
Habitat
The leaf warblers are denizens of diverse habitats, including wet tropical forest, bamboo forest, brushy scrub, gardens, and northern deciduous and boreal forests.
Diet and Foraging
Phylloscopids are primarily insectivorous, obtaining prey by gleaning, hover-gleaning, or flycatching.
Breeding
The leaf warblers appear to be monogamous with biparental care, although some species may be polygynous, mating with a second female on a separate territory. Their nests are typically domed structures built mainly of grass, leaves, and lichens, and are often lined with fine grass. Leaf warblers typically place their nest on or near the ground in a well-concealed location. Females lay 2 to 9 eggs. Nest-building and incubation is by both sexes or by the female alone, and both male and female feed the chicks. Incubation takes 13 to 14 days, and the chicks leave the nest after 10 to 22 days. They appear to be fed by parents for up to a month after fledging.
Conservation Status
Habitat loss is the primary conservation concern for the four species (6%) that are at risk (1 NT, 3 VU). The Kolombangara Leaf Warbler Seicercus amoenus, Hainan Leaf Warbler Phylloscopus hainanus, and Izu Leaf Warbler P. ijimae are considered vulnerable, all of them restricted-range species on islands. In addition to the special risk attached to small populations sizes, there is also concern about mortality related to pesticide use on the wintering grounds of P. ijimae.
Systematics History
Phylloscopidae is part of the superfamily Sylvioidea of oscine passerines. This family was traditionally placed in the large family Sylviidae sensu lato. Recent molecular phylogenetic studies, however, suggest that Phylloscopidae is a distinct clade within the larger Sylvioidea. Within this broader radiation, Phylloscopidae is in a clade with Aegithalidae and Scotocercidae (Gelang et al. 2009, Olsson et al. 2013), and the relationships among these three families vary slightly among studies. Phylloscopidae could be sister to a clade that is Aegithalidae and Scotocercidae taken together (Alström et al. 2011a, Irestedt et al. 2011, Fregin et al. 2012, Alström et al. 2013a), or sister to Aegithalidae and then together sister to Scotocercidae (Johansson et al. 2008b) or vice versa (Olsson et al. 2013).
Conservation Status
Least Concern |
83.8%
|
---|---|
Near Threatened |
6.2%
|
Vulnerable |
2.5%
|
Endangered |
0%
|
Critically Endangered |
0%
|
Extinct in the Wild |
0%
|
Extinct |
0%
|
Not Evaluated |
0%
|
Data Deficient |
0%
|
Unknown |
7.5%
|
Data provided by IUCN (2023) Red List. More information