Henslow's Sparrow

(Ammodramus henslowii)

Status: Endangered (ESA 2008, SARA 2003)

Table of Contents:

Species Identification
Diet
Habitat and Range
Biology and Behaviour
Similar Species
Threats/Reasons for Being Endangered
Conservation and Recovery Strategies
How You Can Help

Species Identification:

The Henslow’s Sparrow is a small songbird, mostly brown with an intricately patterned back and wings. Their head is mostly olive green with to black stripes along the crown. Their body has flecks of dark brown, chestnut brown and white. The Henslow’s Sparrow has a unique call that is often mistaken for an insect call- it is quick, high pitched and metallic. In fact, most of the sounds that make up the call is too high for human ears to hear, so it is much more complex than it sounds.

Diet:

Their diet is primarily made up of grassland insects like grasshoppers, beetles, and caterpillars during the breeding season, and during the winter they will eat mostly seeds and berries. The Henslow’s Sparrow feeds mainly from off the ground and prefers open, undisturbed grasslands to forage.

Map taken from Wildlife Species Canada: https://wildlife-species.canada.ca/species-risk-registry/virtual_sara/files/cosewic/sr_henslows_sparrow_0911_eng.pdf

Habitat and Range:

The Henslow’s Sparrow’s breeding range centers around the Great Lakes, extending west to Nebraska and Kansas, and south as far as Tennessee. It extends to the perimeters of Lake Erie and Lake Ontario. Within Canada the Henslow’s Sparrow is only found in southern Ontario, and a small part of southern Quebec. Breeding Bird Atlas surveys have identified sightings just east of Lake Simcoe in the Land Between. Their range used to extend further and into Quebec before natural grasslands were converted for agricultural use and urban expansion. The wintering range includes most of the southeastern states on the Gulf Coast including Texas, across to Florida, and the Carolinas.

The ideal habitat for breeding Henslow’s Sparrows is a large grassland (>30 hectares) with low-lying wet areas, a thick layer of dead vegetation, and no woody vegetation. Tall grasses (>30 cm high) are preferred. While they used to live in natural grasslands, today they are more commonly found in pastures and crop lands. They may also nest in hayfields, which is becoming increasingly dangerous with early harvests that often occur during their nesting season.

Biology and Behaviour:

The Henslow’s Sparrow is hard to find since they stay hidden amongst dense grasses, and generally prefer running along the ground than flying. Adults arrive at their breeding grounds beginning in late April, rarely returning to the same site as previous years. The female arrives a week after the male, and constructs a nest close to the ground amongst tufts of grass. The male may be seen while perched on shrubs to sing. They will sing throughout the breeding season, especially at night. An average of 4 eggs are laid, and multiple clutches are common. Females incubate the eggs for 8 to 10 days, then both parents feed the nestlings. In August, adults undergo a post-breeding molt before their fall migration.

Similar Species:

They may be confused with several other sparrow species, especially the Grasshopper Sparrow. The Henslow’s Sparrow can be distinguished by its flat head, shorter tail, and lightly streaked pale chest

Threats/ Reasons for being at Risk:

1. Loss of habitat in breeding grounds: Historically, tall grass prairie habitats were converted to pasture, crops, or forests. Intensive agricultural practices also leave only limited times without disturbance. Heavy mowing, heavy grazing by livestock, and early harvesting disrupts the sparrows’ life stages and destroys their nests and feeding grounds.

2. Drainage of wetlands and wet grasslands: Wetlands and wet grassland habitats are being destroyed by development. It is estimated that southern Ontario has lost 70% of its wetlands to development and agriculture. The Henslow’s Sparrow needs large amounts of undisturbed grassland habitat, which is becoming increasingly rare as roads and urban centers begin to split up large areas of intact wilderness.

3. Fire suppression: Natural wildfires are very important for grasslands since they increase species diversity and keep the grasslands from transitioning into forest habitats, or allowing invasive species to take over. Fire suppression allows successional encroachment of meadows, and allows these forests to become very dense.

4. Climate Change: The Henslow’s Sparrow and its habitat is sensitive to extreme weather events like drought or flash flooding, both of which are becoming more and more common. They are also at risk in the spring if there are sudden cold snaps, as well as during migration if there are any intense storms.

Conservation and recovery strategies:

The Ontario Government intends to begin Henslow’s Sparrow recovery by setting aside 50 hectares of suitable grassland habitat that is capable of supporting up to 10 Henslow’s Sparrow pairs. They have committed to protecting the sparrow’s habitat through the Endangered Species Act, and encourage collaboration amongst different agencies working on the issue. They aim to increase the amount of grassland habitat available using private property through education and stewardship (including the development of Best Management Practices, BMPs).

The American Fish and Wildlife Service’s recovery plan focuses on filling in knowledge gaps through research on the species range behaviour. They also intend to protect, maintain, and restore native grassland habitat. Reclaimed mine sites may also be converted into suitable habitat if they are maintained properly.

How can you help?

Farmers should follow Best Management Practices (BMPs) for grassland bird management on their property. For instance, follow this guide by the Ontario Soil Corp. It outlines suggestions for rotational grazing, and timing your hay mowing to reduce disturbance on nesting birds.
Landowners with nesting Species at Risk on their property may be eligible for government funds through the Species at Risk Stewardship Fund, Species at Risk Research Fund for Ontario, or the Species at Risk Farm Incentive Program.
Donate time or money to your local land trust or nature conservancy to help protect and restore native grasslands in Ontario.
Support farmers who follow BMPs by asking questions at farmers markets or farm stands.

Quick Facts:

This bird was named after John Stevens Henslow, who was a botanist, a teacher of Charles Darwin, and a friend of John James Audubon
The Henslow’s Sparrow sings most often at dawn and dusk, but will also sometimes sing throughout the night
It is difficult to get proper population estimates of the Henslow’s Sparrow in Canada because they do not return to the same sites each year, and they stay very well hidden amongst tall grass
The oldest recorded Henslow’s Sparrow was found in Louisiana and was 6 years old

Additional Resources:

Cornell Lab of Ornithology profile
See the Ontario Government’s response statement for actions they will take
Ontario Soil Corporation’s Best Management Practices guide for farmers

Sources:

COSEWIC. 2010. COSEWIC Assessment and Status Report on the Acadian Flycatcher (Empidonax virescens) in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. X + 38 pp.

Environment Canada. 2012. Recovery strategy for the Acadian Flycatcher (Empidonax virescens) and the Hooded Warbler (Wilsonia citrina) in Canada. Species at Risk Act Recovery Strategy Series. Environment Canada, Ottawa, Ontario. viii + 32 pp.

Ontario Ministry of Natural Resources and Forestry. 2016. Recovery Strategy for the Acadian Flycatcher (Empidonax virescens) in Ontario. Ontario Recovery Strategy Series. Prepared by the Ontario Ministry of Natural Resources and Forestry, Peterborough, Ontario. v + 5 pp. + Appendix.