BIRD OF THE WEEK: May 26, 2017
SCIENTIFIC NAME: Ammodramus savannarum
POPULATION: 31 million
HABITAT: Breeds and winters in grasslands, including prairies, pastures, meadows, and old fields
More often heard than seen, the secretive Grasshopper Sparrow gets its name for the buzzing, insect-like quality of its songs. When seen among the dense grasses where it breeds, this small, short-tailed bird appears big-headed and large-billed compared to other sparrows.
Habitat loss and degradation remain the greatest threats to Grasshopper Sparrow and other grassland-dependent species such as Baird's Sparrow, Long-billed Curlew, and Bobolink. Increased use of pesticides, brood parasitism by Brown-headed Cowbirds, and loss of wintering habitat have also contributed to population declines.
Twelve subspecies of Grasshopper Sparrow are recognized. Of the Florida subspecies (Ammodramus savannarum floridanus), fewer than 200 birds remain, all in the dry prairie ecosystems of that state. This subspecies is listed as Endangered by the U.S. Fish and Wildlife Service under the Endangered Species Act.
Most Grasshopper Sparrow populations are migratory, wintering in the southern United States, Mexico, and western Central America. (ABC's Aditi Desai encountered wintering sparrows and many other grassland species during a recent trip to Mexico's Chihuahuan Desert grasslands.)
During the breeding season, Grasshopper Sparrows prefer areas with expanses of grassy habitat and very few trees.
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This species forages mainly on the ground, keeping a low profile as it walks or runs through grasses. True to its name, the Grasshopper Sparrow feeds on grasshoppers during the breeding season, along with other insects, spiders, earthworms, and snails.
Grasshoppers can be large prey for a small bird, but the sparrow has a technique to make eating them easier. The bird immobilizes its grasshopper prey by pinching the insect behind the head, then shakes the legs off before eating it or feeding it to their young.
In the fall and winter these sparrows mainly eat grass seed and waste grain.
Shortly after arriving at the breeding grounds, the male Grasshopper Sparrow sings and performs flight displays to establish his territory. Females arrive three to five days later, and the birds quickly form pair bonds.
Both males and females sing, and Grasshopper Sparrow is one of the few sparrow species in which the male sings two different songs: one to attract a mate and another to defend a breeding territory.
After mating, female Grasshopper Sparrows build well-hidden, cup-shaped grass nests on the ground. They tend to hide the location of their nests, and seldom fly directly to them, instead landing a short distance away and slipping through the grass to the nest entrance.
Similarly, when leaving, the parent birds often run from the nest, taking flight at a distance to avoid signaling the nest's location. Like Black-necked Stilt and some other birds, adults perform broken-wing displays near nests or fledglings to draw predators away.
The female incubates her clutch of three to six eggs for up to 13 days and sometimes has “helpers” (young from previous broods) to assist with feeding and brooding nestlings. Grasshopper Sparrows may produce a second or even a third brood in the same season, though the first clutch tends to be the largest. Females can build a new nest while feeding larger young in the active nest, sometimes with as little as three days between nesting attempts.
If you're lucky enough to own a piece of grassland where Grasshopper Sparrows nest, you can help these birds. Avoid mowing between late April and July to let the birds produce up to three successful nests, about one a month. (The same rules apply to roadsides in agricultural settings.) If you must mow in this time period, mow early and often to avoid creating a population “sink”—an area that attracts nesting birds but where they're unsuccessful in producing offspring.
Partners in Flight classifies the Grasshopper Sparrow as a “Common Bird in Steep Decline.” This sparrow has lost 68 percent of its population since 1970, mainly due to loss and fragmentation of its grassland habitats. In addition to the ESA protection of the Florida subspecies, the entire species has been identified as a focal species for conservation by the U.S. Fish and Wildlife Service, and an Assessment and Conservation Plan has been developed.
ABC works with partners across the Americas to preserve and restore grassland habitats, helping to ensure a future for species including Grasshopper Sparrow and Sprague's Pipit. Our work with landowners through the Oaks and Prairies and other Migratory Bird Joint Ventures has also yielded positive conservation results.
Learn about our new BirdScapes approach to conserving migratory birds—another way we're working to save breeding, wintering, and stopover habitat for birds where they need it most.
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