Endangered Species Survey work determines whether a development site harbors federally or state-listed threatened and endangered species — and what that means for your project timeline, permits, and costs. In Illinois, construction projects near prairies, wetlands, and mature forests increasingly trigger the need for an Endangered Species Survey before ground can be broken.
A3 Environmental Consultants (A3E) performs Endangered Species Survey assessments across Illinois, with particular expertise in the species most likely to affect construction schedules: the Rusty Patched Bumble Bee, Northern Long-Eared Bat, and Hine’s Emerald Dragonfly.
Tallgrass prairie habitat — critical for Rusty Patched Bumble Bee surveys
When Is an Endangered Species Survey Required?
An Endangered Species Survey is triggered when a project involves federal funding, federal permits, or activities on federal land — activating Section 7 of the Endangered Species Act (ESA). In practice, most Illinois construction projects encounter this requirement through one of three pathways:
- USACE Section 404 permits: Any project that fills wetlands or impacts waters of the U.S. requires a federal permit, which triggers ESA Section 7 consultation and typically requires an Endangered Species Survey
- IDOT and Tollway projects: Federally funded transportation projects require biological clearance before construction. A3E supports IDOT contractors with IPaC reviews and field surveys.
- USFWS IPaC screening: The USFWS Information for Planning and Consultation (IPaC) system flags species that may be present in a project area. When IPaC identifies potential species, field verification through an Endangered Species Survey is the next step.
Illinois also requires state-level screening through IDNR’s EcoCAT (Ecological Compliance Assessment Tool) system. EcoCAT checks for state-listed species, Illinois Natural Area Inventory (INAI) sites, and Nature Preserves near a project area. When EcoCAT returns a positive result, field assessment is typically required.
Illinois Species That Trigger Endangered Species Surveys
Not every project triggers a full survey. The species present in a project area — and their habitat requirements — determine what level of assessment is needed. Here are the species most commonly encountered on Illinois construction projects:
Mature hardwood forest with snag trees — Northern Long-Eared Bat habitat
Rusty Patched Bumble Bee (Bombus affinis) — Federally Endangered
The Rusty Patched Bumble Bee is the species most likely to affect project timelines in northern Illinois. Found in grasslands, prairies, and areas with diverse native flowering plants, this species has been documented in DuPage, Cook, Kane, and Lake counties. Projects in or near suitable habitat may require presence/absence surveys during the active season (April through October). A3E has conducted Rusty Patched Bumble Bee surveys at multiple sites including habitat enhancement projects in Cook County across the Chicago metropolitan area.
Northern Long-Eared Bat (Myotis septentrionalis) — Federally Endangered
This bat species roosts under bark and in cavities of mature trees during summer and hibernates in caves and mines during winter. The primary impact on construction projects: tree clearing restrictions from April 1 through September 30 in areas where the species may be present. This seasonal window is the single most common construction schedule impact from the Endangered Species Act in Illinois. A3E performs habitat assessments to determine whether tree clearing restrictions apply to a specific project site.
Indiana Bat (Myotis sodalis) — Federally Endangered
Similar habitat requirements to the Northern Long-Eared Bat, with roosting in trees during summer and cave hibernation in winter. Indiana Bat presence triggers the same April-September tree clearing restrictions and may require mist-net surveys or acoustic monitoring to confirm presence.
Hine’s Emerald Dragonfly (Somatochlora hineana) — Federally Endangered
Found in calcareous wetlands and fens, primarily in Cook and DuPage counties. Projects near spring-fed wetlands or fen habitat may require specialized surveys. This is one of the rarest dragonflies in North America.
Calcareous fen habitat — home to Hine’s Emerald Dragonfly
Eastern Prairie Fringed Orchid (Platanthera leucophaea) — Federally Threatened
A rare orchid found in wet prairies and sedge meadows. Projects that impact high-quality prairie habitat in northern Illinois may need botanical surveys during the June-July flowering period to confirm presence or absence.
Eastern Massasauga Rattlesnake (Sistrurus catenatus) — Federally Threatened
A small rattlesnake inhabiting wetlands and prairies. While its range in Illinois has contracted significantly, projects in known habitat areas may require visual encounter surveys.
What an Endangered Species Survey Involves
The scope of an Endangered Species Survey depends on which species are flagged and what habitat is present. A typical survey process includes:
- Desktop screening: IPaC review (federal species), EcoCAT review (state species), Illinois Natural Heritage Database check, and review of known occurrence records within the project vicinity
- Habitat assessment: Field evaluation to determine whether suitable habitat exists on or adjacent to the project site. This is the most common Endangered Species Survey deliverable — many projects stop here if habitat is absent.
- Presence/absence surveys: Species-specific field protocols conducted during appropriate seasonal windows. Methods vary by species: visual transect surveys for bumble bees, acoustic monitoring or mist-netting for bats, botanical surveys for listed plants.
- Biological assessment: Formal Section 7 documentation submitted to USFWS for projects with federal nexus. Includes species evaluation, effects determination, and proposed conservation measures.
How an Endangered Species Survey Affects Your Project
The most common impact is seasonal construction restrictions. If the Northern Long-Eared Bat or Indiana Bat may be present, tree clearing cannot occur between April 1 and September 30 without either a negative habitat assessment or species-specific clearance. For large construction projects, this six-month window can significantly affect scheduling if not identified early.
The key to managing this risk: conduct the Endangered Species Survey during the planning phase, not after construction mobilization. A3E recommends completing species screening and habitat assessment during the design or due diligence phase so that any seasonal restrictions are built into the construction schedule from the start — avoiding costly delays and change orders.
A3E Endangered Species Survey Capabilities
Following the 2024 acquisition of Olson Ecological Solutions, A3 Environmental Consultants fields a team of dedicated ecologists with direct experience in Illinois threatened and endangered species. A3E’s Ecological Services team provides:
- IPaC and EcoCAT screening for federal and state-listed species
- Habitat assessments for Rusty Patched Bumble Bee, Northern Long-Eared Bat, Indiana Bat, and other listed species
- Presence/absence field surveys using USFWS-approved protocols
- Biological assessments and Section 7 consultation support
- IDNR Incidental Take Authorization applications
- Construction timing recommendations and tree clearing window management
- Long-term restoration monitoring that tracks species recovery post-construction
- Support for wetland delineation and jurisdictional determination projects that trigger species screening
Frequently Asked Questions
What is an Endangered Species Survey?
An Endangered Species Survey is a field assessment that determines whether federally or state-listed threatened and endangered species are present on or near a project site. The survey may include desktop screening, habitat evaluation, and species-specific presence/absence surveys depending on what species are flagged for the area.
How much does an Endangered Species Survey cost?
Costs range from $1,500 to $2,500 for a desktop screening and habitat assessment, up to $5,000 to $15,000+ for full-season presence/absence surveys with multiple species. The scope depends on which species are flagged, habitat complexity, and site size. A3E provides project-specific scoping to match the survey level to what regulators actually require.
How long does an Endangered Species Survey take?
Desktop screening and habitat assessments can be completed in 2 to 4 weeks. Presence/absence surveys are constrained by seasonal windows — bumble bee surveys run April through October, bat surveys June through August, and botanical surveys during species-specific flowering periods. Plan accordingly.
What happens if endangered species are found on my site?
A positive finding does not necessarily stop your project. It triggers a Section 7 consultation with USFWS to develop avoidance, minimization, or mitigation measures. Common outcomes include seasonal construction restrictions, habitat buffers, or compensatory conservation measures. A3E manages this consultation process for clients.
Does every construction project need an Endangered Species Survey?
No. Only projects with a federal nexus (federal funding, federal permits, or federal land) are required to address the Endangered Species Act. However, Illinois state-level screening through EcoCAT is required for many local permits and is recommended as due diligence on any project near natural areas.
Schedule an Endangered Species Survey
Seasonal windows are limited — early planning prevents construction delays. A3 Environmental Consultants provides Endangered Species Survey services across Illinois with the ecological expertise to deliver defensible results that satisfy both USFWS and IDNR requirements.
Contact A3E About Endangered Species Surveys →
Call us at (888) 405-1742 or email Info@A3E.com.
Reviewed by Tim Allen, A3 Environmental Consultants
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