
Study: Starvation and a Freak Snow Storm Caused the Southwest's Mass Bird Die-Off
A record death event during fall migration sent experts scurrying for an explanation. In the lab results, they see a common factor: climate change.
Adult female. Photo: Becky Matsubara/Flickr (CC BY 2.0)
Cardellina pusilla
Conservation status | Numbers probably stable. Adaptable in its choice of wintering habitats, probably not threatened by cutting of forests in the tropics. |
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Family | Wood Warblers |
Habitat | Thickets along wooded streams, moist tangles, low shrubs, willows, alders. Breeds as far north as timberline, in thickets, second-growth, bogs, or in alder and willow groves near streams and ponds. In migration and winter, occurs from hot lowland thickets up to cool mountain woods; always in scrubby overgrown clearings and thin woods, not in the interior of dense forest. |
Feeds usually within 10' of ground, searching actively among foliage of bushes. Hops on ground to probe among fallen leaves, and flutters up to take items from the undersides of leaves. Frequently flies out to catch flying insects in mid-air.
4-6, sometimes 2-7. Creamy white with variable marks of brown. Incubation is by female only, 10-13 days. Cowbirds regularly lay eggs in nests of this species. Young: Fed by both parents; brooded by female only. Young leave the nest about 8-13 days after hatching. Normally 1 brood per year.
Fed by both parents; brooded by female only. Young leave the nest about 8-13 days after hatching. Normally 1 brood per year.
Mostly insects. Presumably feeds mostly on insects, like other warblers. Frequent items in diet include bees, wasps, beetles, caterpillars, and aphids. Also eats some spiders, and sometimes berries. In winter in the tropics, sometimes feeds on protein corpuscles found at the bases of leaves of Cecropia trees.
Populations that nest along Pacific Coast tend to lay fewer eggs and raise fewer offspring per nesting attempt, and males mate with only one female. Populations that nest in high mountains of West tend to lay more eggs per clutch and fledge more young, and some males have more than one mate. Nest: Usually on ground, sunken in moss or sedges, often at base of shrub. Along Pacific Coast, nests often placed up to 3' above ground, in shrubs or vines. Nest is bulky open cup, built by female, made of dead leaves, grass, and moss; lined with fine grass and hair.
Audubon’s scientists have used 140 million bird observations and sophisticated climate models to project how climate change will affect this bird’s range in the future.
Zoom in to see how this species’s current range will shift, expand, and contract under increased global temperatures.
Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.
A record death event during fall migration sent experts scurrying for an explanation. In the lab results, they see a common factor: climate change.
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