Special Status Updates for Two Emblematic California Species

by Jason Yakich

WRA’s wildlife team has been tracking recent legal changes related to two species of conservation concern in California – the tricolored blackbird and monarch butterfly.  The following is a summary of the proposed changes and potential implications of these regulatory updates.

Tricolored Blackbird

Overview

Tricolored blackbird (photo credit Wikipedia, Monte M Taylor)

Tricolored blackbird
(photo credit Wikipedia, Monte M Taylor)

The tricolored blackbird (Agelaius tricolor) is virtually endemic to California and extremely gregarious by land-bird standards, nesting in dense, often enormous colonies (up to tens of thousands of pairs) where nests are placed within a few feet of each other.  Typical nesting habitat consists of dense, tall emergent vegetation (tules, cattails, etc.) within inundated freshwater wetlands; riparian vegetation and other dense growth near water (e.g., blackberry brambles) as well as certain types of grain fields are also used.  Insects are the primary food, particularly grasshoppers, beetles, and caterpillars.  Given the ephemeral nature of the habitat and associated forage, tricoloreds are adapted to roaming across the landscape and rapidly forming nesting assemblages when and where local conditions are suitable. Tricolored blackbird has been named a Species of Special Concern by California Department of Fish and Wildlife (CDFW) since 1990 due to its near-endemism at the state level and the fact that the species relies heavily on threatened habitats in the Central Valley.  Following the continued decline of the statewide population, the tricolored was temporarily emergency-listed as Endangered by the California Fish and Game Commission in December 2014.

Potential Impacts

Following expiration of the emergency listing, the tricolored is now a formal candidate for listing at the state level while available scientific information is reviewed.  Formal candidates for listing (state and federal) are typically treated as listed during environmental review processes.  Thus, it is anticipated that CDFW will now require Incidental Take Permits, also known as 2081 permits, for impacts to tricolored nesting sites, and also potentially requiring compensatory mitigation under CEQA for impacts to surrounding foraging habitat.  Foraging habitat is highly variable and in addition to wetlands includes grassland, scrub, and increasingly, modified open lands such as pastures and agricultural plots.  Tricolored foraging typically occurs within approximately three miles of breeding sites, and CDFW may come to use this distance as a general handle for estimating foraging habitat impacts.  In some cases, field studies may be needed to determine where foraging effort by a given breeding colony is focused.  It is also worth noting that a “patchwork” landscape featuring various habitats and land use types is capable of supporting tricoloreds, provided that insect resources are abundant.  For this reason, conservation easements and land management plans that allow for other land uses (in addition to tricolored conservation) may be especially useful, and would provide land owners and project proponents more options than would be available for other sensitive species.

Considerations

The tricolored is closely related to and very similar in appearance to the broadly-distributed red-winged blackbird (A. phoeniceus).  Although habits of the two are similar, red-wingeds are more generalist and commonly nest in drier, weedy/brushy areas that would be considered marginal if not unsuitable for tricoloreds.  Additionally, red-wingeds are less intensely colonial.  Dependent on the local population in question, red-wingeds in California have either a bright yellow band below the “red-wing” marking, or no band, versus the whitish band of the tricolored.  Differences between the respective females are very subtle.  The songs of the two species are also similar, although the tricolored version is harsher; many observers have likened the sound of a colony in chorus to a group of cats fighting.

Monarch

Overview

Monarch (photo credit Shawn Carroll)

Monarch (photo credit Shawn Carroll)

The monarch (Danaus plexippus) is a large, showy orange and black butterfly, and one the few species readily identifiable by laypeople.  Monarchs are somewhat famous in California, particularly because many thousands overwinter in the state.  Many of these wintering individuals migrate in from outside of California, but a portion of this population also breeds within the state.

Most wintering sites are located on the coast, and consist of groves or lines of trees that provide suitable shelter and thermal characteristics.  Essentially, the trees must shelter butterflies from wind and rain while also providing sufficient solar exposure to allow butterflies to warm.  The presence of nectar plants is also essential.  Trees commonly used in this context are eucalyptus, Monterey cypress, and Monterey pine.  The larval host plant is milkweed (Asclepias spp.), of which there are 15 native and one non-native species in California.

While the monarch itself does not currently have legal protection, CDFW recognizes it as a “Special-status Invertebrate” and tracks its known communal wintering sites.  As such, conservation measures are often applied to these sites within the context of both CEQA and local environmental review processes.  In October 2015, the California legislature passed Assembly Bill 559, which brings renewed conservation attention to the monarch.  While the legal status of the butterfly remains unchanged, the bill amends the California Fish and Game Code to allow CDFW to “…take feasible actions to conserve monarch butterflies and the unique habitats they depend upon for successful migration.”  To this end, CDFW “shall use the best available science” to restore or revegetate both milkweed habitat and nectar plants, and wintering habitats, and also to increase the number of partnerships involving both public and private entities to promote monarch conservation.

Potential Impacts

A. speciosa: showy milkweed (photo credit Aaron Arthur)

A. speciosa: showy milkweed (photo credit Aaron Arthur)

While AB 559 appears to mostly reinforce existing CDFW procedures regarding wintering sites, the focus on milkweed habitat is more novel.  While it remains to be seen exactly how CDFW will encourage milkweed conservation, likely approaches include treating all native milkweeds as sensitive (three species already enjoy this status), particularly in areas considered important for the state’s breeding monarch population.  CDFW’s regulatory oversight manifests in various forms but is most commonly encountered in Streambed Alternation Agreements (1602s) and within CEQA analyses.   AB 559 specifically encourages the restoration of not only milkweeds but also wintering habitat.  This approach suggests that various mitigation options for impacts to monarch habitat may develop, including on-site restoration or enhancement of vegetation communities that support monarchs throughout the year.  Milkweeds are relatively easy to grow from seed, and landowners could include them in landscaping plans for sites where monarch conservation is anticipated to be an issue during environmental review and/or the permitting process.

Please contact us if your project includes considerations for special status species or you would like more information about WRA’s wildlife and regulatory expertise.