Plants and Animals
Botaurus lentiginosus American bittern
Key Characteristics
This brown, medium sized heron is 23 – 33 inches (60 – 85 cm) in length with a stout body and neck and relatively short legs. Adults are dark brown above, heavily streaked brown and white below, with a rusty crown and white throat. A long black patch extends from below the eyes down each side of the neck, which is a character unique among the herons. Previous authors have best described the American bittern’s low, resounding song as a deep, gulping, pounding “BLOONK-Adoonk”, which is repeated one to 10 times in succession and can be heard from as far away as 1/2 mile.
Status and Rank
US Status: No Status/Not Listed
State Status: SC - Special Concern (rare or uncertain; not legally protected)
Global Rank: G5 - Secure
State Rank: S3 - Vulnerable
Occurrences
| County | Number of Occurrences | Year Last Observed |
|---|---|---|
| Alger | 3 | 2022 |
| Arenac | 1 | 2007 |
| Baraga | 1 | 2015 |
| Bay | 3 | 2019 |
| Charlevoix | 1 | 2019 |
| Cheboygan | 1 | 1998 |
| Chippewa | 13 | 2018 |
| Crawford | 1 | 2023 |
| Delta | 4 | 2022 |
| Gratiot | 1 | 2003 |
| Houghton | 1 | 2015 |
| Huron | 2 | 2007 |
| Iosco | 1 | 2019 |
| Jackson | 5 | 1996 |
| Kalamazoo | 1 | 1973 |
| Kalkaska | 1 | 2023 |
| Leelanau | 1 | 2019 |
| Livingston | 1 | 1989 |
| Luce | 1 | 2022 |
| Mackinac | 4 | 2013 |
| Macomb | 1 | 2004 |
| Manistee | 1 | 2005 |
| Marquette | 1 | 2012 |
| Mason | 1 | 2005 |
| Monroe | 1 | 2019 |
| Muskegon | 1 | 2018 |
| Ottawa | 1 | 2021 |
| Saginaw | 2 | 2018 |
| St. Clair | 2 | 2017 |
| Tuscola | 2 | 2007 |
| Washtenaw | 1 | 1989 |
| Wexford | 1 | 2013 |
Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.
Habitat
American bitterns nest and forage in a wide variety of wet to wet-mesic habitats with herbaceous or herbaceous-shrub cover. They are area-dependent and are typically found only in the larger wetlands.
Natural Community Types
- Coastal fen
- Coastal plain marsh
- Emergent marsh
- Great lakes marsh
- Lakeplain wet prairie
- Lakeplain wet-mesic prairie
- Northern fen
- Northern wet meadow
- Poor fen
- Southern wet meadow
- Wet prairie
- Wet-mesic sand prairie
For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.
Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.
Management Recommendations
Preservation of freshwater wetlands, especially large shallow wetlands with dense growth of robust emergent vegetation, is the most urgent management need for this species. Programs that provide funds for wetland restoration and protection on private and public lands can effectively conserve habitat for this species and need to continue. Such initiatives include Farm Bill programs like the Wetlands Reserve Program and Conservation Reserve Program, and the North American Waterfowl Management Plan, which uses funding appropriated through the North American Wetlands Conservation Act. Existing wetlands also need to be protected from chemical contamination, siltation, eutrophication, and other forms of pollution that could harm the birds or their prey. Encouraging best management practices, such as filter strips, no-till farming, and conservation tillage, in surrounding watersheds would help protect priority habitats from pollution.
Active Period
Migration from first week of April to fourth week of April
Migration from first week of September to fourth week of October
Nesting from first week of May to first week of August
Survey Methods
Because the American bittern is most often concealed in dense herbaceous wetlands, the best time to survey for this species is during the breeding season when it is more apt to call to mark its territory or advertise for a mate. Singing is most often crepuscular and nocturnal, but American bitterns can be heard throughout the day and night early in the breeding season. Conspecific call-response techniques have been used successfully to improve the effectiveness of surveys for American bitterns and other marsh-nesting birds.
Broadcast conspecific call
Survey Period: From fourth week of April to first week of July
Time of Day: Morning (sunrise)
References
Survey References
- Bibby, C.J., N.D. Burgess, and D.A. Hill. 1992. Bird Census Techniques. Academic Press, New York.
Technical References
- Monfils, M.J. 2004. Special Animal Abstract for Botaurus lentiginosus (American bittern). Michigan Natural Features Inventory, Lansing, MI. 6pp.
- Sibley, D.A. 2000. The Sibley Guide to Birds. Knopf, Toronto. 544pp.