Plants and Animals

Siren intermedia nettingi Western lesser siren

Key Characteristics

Western lesser sirens are aquatic salamanders ranging in size from 7-20 inches (18-50 cm). They have bushy, reddish gills, elongate, eel-like bodies, and a vertically flattened tail. Western lesser sirens have tiny front legs with four toes on each foot and lack hind legs. They are dark gray, olive, or brown in color with scattered dark spots (though some specimens can be very dark, almost black). Mudpuppies are a confusing species since they too have bushy external gills, but are not eel-like, and mudpuppies have four legs (sirens only have front legs). Western lesser sirens are only known from the southwestern corner of Michigan.

Status and Rank

US Status: No Status/Not Listed
State Status: E - Endangered (legally protected)
Global Rank: G5 - Secure
State Rank: S1 - Critically imperiled

Occurrences

County	Number of Occurrences	Year Last Observed
Van Buren	2	2021

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

Lesser western sirens are found in ponds, ditches, sluggish streams, shallow lakes, and backwater sloughs. Sites with muddy bottoms and an abundance of aquatic plants are preferred.

Natural Community Types

Headwater stream (1st-2nd order), pool
Inland lake, littoral, benthic

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

Sirens are secretive and inconspicuous, and it is possible that more sites in the lower Lake Michigan drainage basin will be found. The use of rotenone, a pesticide used to kill fish, should not be applied to sites that contain sirens.

Active Period

Breeding from first week of May to fourth week of June

Survey Methods

Methods for capturing sirens have changed over time. Electric fish shockers have proved effective at rousting sirens from their hiding places during the day. Some researchers did not discover the presence of sirens in a lake until electrofishing was used, although a variety of netting techniques had been tried earlier. They suggested that seining was probably ineffective because the sirens are buried in the bottom mud during the day. Others were also successful using rotenone, but sirens did not appear to be affected until they left their burrows after sunset. It is noteworthy that both of the two known Michigan populations were discovered when rotenone was applied to the shallow inlets of lakes for fish management purposes (Harding, 1997). More recently, minnow traps have been successfully used to trap lesser sirens.

Electroshocking

Survey Period: From first week of April to fourth week of August

Minnow traps