Artificial Lighting May Shift Bird Migration by More Than a Week, New Research Says
Purple Martins exposed to bright nighttime light migrated eight days early—which could lead to starvation at their breeding grounds.
Adult male. Photo: Agami Photo Agency/Shutterstock
Progne subis
Conservation status | Has declined seriously in parts of the west, and currently declining in the east. Reasons are not well known, but competition with starlings for nest sites may be involved. |
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Family | Swallows |
Habitat | Towns, farms, semi-open country near water; in west, also mountain forest, saguaro desert. In the east, breeds in any kind of semi-open area where nest sites are provided, especially near a pond or river. More local in the west, with isolated colonies breeding around woodland edges, clearings in mountain forest, and lowland desert with giant saguaro cactus. |
Forages almost entirely in the air. May forage very low over water, or quite high at times. Occasionally walks about on ground to pick up insects, perhaps mostly in harsh weather.
4-5, sometimes 3-8. White. Incubation is by female, 15-18 days. Young: Both parents feed nestlings. Young leave nest about 26-31 days after hatching.
Both parents feed nestlings. Young leave nest about 26-31 days after hatching.
Insects. Feeds on a wide variety of flying insects, including many wasps and winged ants, and some bees; also many true bugs, flies (including house flies and crane flies), beetles, moths, and butterflies. Dragonflies may be an important part of diet. Also eats some spiders. The old claim of martins eating "2,000 mosquitoes a day" apparently has no basis in fact.
Males return to nesting areas first in spring, establish nesting territories. Usually nests in colonies, especially in east, where almost all are in multiple-roomed nest boxes put up for them. Western martins may nest in looser colonies or as isolated pairs. Male will sometimes have more than one mate. Nest: Natural sites are in cavities, mostly old woodpecker holes, in trees (or in giant cactus in southwest). In the east, most martins now use nest boxes. Sometimes nests in holes in buildings or cliffs. Nest (built by both sexes) is cup of leaves, grass, twigs, debris, and usually mud. Nest may have raised dirt rim in front to help keep eggs from rolling out.
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.
Purple Martins exposed to bright nighttime light migrated eight days early—which could lead to starvation at their breeding grounds.
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