American Bittern
NDGF
L 28”, WS 42”, 1.5 lb. Long, boldly striped neck with a pointed bill and greenish legs.
Status in North Dakota
Occurs in North Dakota from mid-April to late October. Peak breeding season early June to late July.
Range Map
American Bittern primary (dark gray), secondary (medium gray) and possible/uncommon (light gray) breeding range.
Reason for SWAP Designation
At-risk, ND range important (SGCN b.).
ND ranks 1st out of 26 states for highest percent of the global population (9.62%) during the breeding season (eBird).
The American Bittern is declining, and ND has high stewardship responsibility for this species in the Prairie Pothole Region.
Threats
- Loss of grassland/wetland complexes. Loss and degradation of wetlands, drainage and wetland consolidation.
- Hydrologic shifts in wetlands of the PPR due to wetland consolidation and drainage, climate and land use changes (i.e. lakeification).
- Classified as climate-endangered, American Bittern is projected to lose more than half of its current distribution by 2050, with no net gains of new areas (Audubon).
- Increasing applications of agrochemicals and adverse impacts to water quality, the wetland vegetative community, and the aquatic invertebrate community.
- More frequent or intense harmful algal blooms.
- Aquatic nuisance species spreading and damaging wetland ecosystems.
- Migration routes of American Bitterns using satellite telemetry data found that many birds (63%) breeding in the central part of North America wintered in the Everglades of Florida, an area impacted by a variety of threats.
- Decline in the southern portion of the species range may be linked to declining amphibian populations.
- The American Bittern is at the top of the food chain, and its presence is a good indicator of environmental quality.
- Some mortality with communication towers.
Research and Monitoring
- Habitat requirements and demographics have been extensively researched.
- Additional information is needed on migration and wintering behaviors.
- The Breeding Bird Survey, eBird and Partners in Flight Databases are key sources of information on distribution and population trends.
Management Recommendations
- Protect and conserve areas where complexes of high-density, medium to large wetlands and large blocks of grassland remain intact.
- Use tall, dense native grasses and sedges when replanting or restoring grassland along wetland edges.
- Maintain a wide vegetative margin around wetlands.
- Delay mowing, haying or burning grasslands until after August 1.
- Mow, hay or burn every 2-5 years to maintain residual vegetation.
- Follow beneficial or best practices during the design, siting, construction, operation, and maintenance of tall structures (e.g. transmission lines, communication towers, wind turbines).
Primary Geological Regions
Habitat Associations
Habitat Use
American Bitterns use a variety of freshwater wetlands including seasonal, semi-permanent, temporary, permanent, fens or restored wetlands.
They prefer wetlands which are > 3 ha (~7 acres), average 13.5 ha (~33 acres), with a large amount of tall, emergent vegetation present such as rushes, sedges, cattails, or common reed. Use wetland complexes with adjacent uplands of hayland, CRP, or idle grasslands.
Most commonly nest among dense emergent vegetation over shallow water, 5-20 cm deep. Bitterns will also nest in adjacent uplands of mid to tall (over 30 cm), dense, native or tame grasslands with moderate litter.
Avoid heavily grazed grasslands and tilled land. The bittern’s cryptic color helps it blend into surrounding habitat where it patiently waits for prey species of insects, amphibians, small fish, mammals, or crayfish.