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

CountyNumber of OccurrencesYear Last Observed
Alger 2 2009
Arenac 1 2007
Baraga 1 2015
Bay 3 2007
Charlevoix 1 1999
Cheboygan 1 1998
Chippewa 13 2018
Delta 3 2017
Gratiot 1 2003
Houghton 1 2015
Huron 2 2007
Iosco 1 2019
Jackson 5 1996
Kalamazoo 1 1973
Kalkaska 1 2004
Livingston 1 1989
Mackinac 4 2013
Macomb 1 2004
Manistee 1 2005
Marquette 1 2012
Mason 1 2005
Muskegon 1 2018
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

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

Nesting from first week of May to first week of August

Migration from first week of September to fourth week of October

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.