Grasshopper Sparrow Life History

Habitat

Habitat Grasslands

Grasshopper Sparrows occur in grasslands, prairies, hayfields, and open pastures with little to no scrub cover and often with some bare ground. Birds in the western part of the range can tolerate some brushy habitat but avoid areas that are too overgrown. Winters primarily in grass-dominated fields.

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Food

Food Insects

True to their name, Grasshopper Sparrows eat grasshoppers in summer, though they will take other prey including beetles, caterpillars, bugs, and spiders. They eat mostly seeds in winter, which they glean exclusively from the ground. Exposed bare ground is critical for effective foraging.

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Nesting

Nest Placement

Nest Ground

Grasshopper Sparrows nest on the ground, often at the base of a clump of grass within an extensive patch of tall grasses or sedges.

Nest Description

The nest is usually domed with overhanging grasses and sedges, woven into the adjoining vegetation, with a side entrance. The inside is lined with fine grasses and occasionally hair. The completed nest is about 5 inches in diameter and 3 inches tall.

Nesting Facts
Clutch Size:3-7 eggs
Number of Broods:2-4 broods
Egg Length:0.6-0.8 in (1.5-2.1 cm)
Egg Width:0.6-0.6 in (1.4-1.5 cm)
Incubation Period:11-13 days
Nestling Period:6-9 days
Egg Description:

White with light reddish brown speckles.

Condition at Hatching:

Eyes closed, covered with grayish-brown down.

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Behavior

Behavior Ground Forager

Grasshopper Sparrows tend to walk or run rather than fly, and spend much of their time seeking insects and seeds on bare ground near the cover of dense grasses. Their stealthy behavior and camouflaged plumage allow them to forage far from cover. Males on territory sit atop a grass stalk, often quivering their wings while singing. When flushed they fly a short distance with rapid fluttery wingbeats before dropping into the grass to evade threats on foot. Pairs are seasonally monogamous, maintaining a pair bond throughout the nesting season but splitting up afterward. Grasshopper Sparrows don’t form flocks, though wintering birds can be fairly numerous on appropriate habitat. Predators include Loggerhead Shrikes.

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Conservation

Conservation Common Bird in Steep Decline

Grasshopper Sparrow populations declined by about 2.5% per year between 1966 and 2015, indicating a cumulative decline of 72% over that period, according to the North American Breeding Bird Survey. Partners in Flight estimates a global breeding population of 32 million, but labels the species a Common Bird in Steep Decline with a Continental Concern Score of 12 out of 20. If current rates of decline continue, the species will lose another half of its population by 2065. The federally endangered Florida subspecies of Grasshopper Sparrow has declined rapidly in recent decades despite an intensive recovery plan. Grasshopper Sparrows are especially vulnerable to habitat loss through fragmentation and degradation, and the loss of native prairie habitat to intensive agriculture has reduced populations across its entire range. On the plus side, the species is very responsive to management including prescribed burns, light to moderate grazing, and delayed mowing of hayfields.

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Credits

Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.

North American Bird Conservation Initiative. 2014. The State of the Birds 2014 Report. US Department of Interior, Washington, DC, USA.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Sauer, J. R., J. E. Hines, J. E. Fallon, K. L. Pardieck, Jr. Ziolkowski, D. J. and W. A. Link. The North American Breeding Bird Survey, results and analysis 1966-2013 (Version 1.30.15). USGS Patuxtent Wildlife Research Center 2014b. Available from http://www.mbr-pwrc.usgs.gov/bbs/.

Sibley, D. A. (2014). The Sibley guide to birds, second edition. Alfred A. Knopf, New York, USA.

Vickery, Peter D. 1996. Grasshopper Sparrow (Ammodramus savannarum), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

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