Spring is here and so are the nesting birds: What does it mean for your project?

by Jason Yakich and Patricia Valcarcel, Wildlife Biologists; photo credits Patricia Valcarcel

Changes to interpretations of long-standing protections to birds and their nests has caused confusion for project planning and compliance. We outline the difference between federal and state regulations, current interpretations of these regulations, and what it may mean for your project.  On December 22, 2017, the Solicitor of the Department of the Interior (DOI) issued Opinion M-37050, which clarifies application of the federal Migratory Bird Treaty Act of 1918 (MBTA).  Opinion M-37050 states unequivocally that only actions with the specific intent to kill, harm or capture covered species of birds (including their eggs and young) can result in violations. The subject Opinion “permanently withdraws and replaces” Opinion M-37041, which was issued by the DOI in January 2017 and stated that the MBTA does prohibit non-intentional or incidental killing/harm, at least under many circumstances.  On November 29, 2018, California Department of Fish and Wildlife (CDFW) issued an advisory statement affirming California regulations protecting bird nests including protection against incidental take (take resulting from an otherwise lawful activity).

Legal ambiguity has existed regarding which actions constituted an MBTA violation within the context of the actions’ intent.  High court rulings over the years have been mixed with some courts finding that specific examples of incidental harm were indeed violations, whereas others found the opposite.  It’s worth noting that the various contested legal cases reviewed in either of both of the two Opinions involved actions that were spatially and/or temporally broad, i.e., with the potential to kill/harm relatively large numbers of birds over time.  Additionally, most of these cases involved some form of perceived negligence on the part of the defendants as well, meaning that corrective measures to avoid or reduce bird deaths/harm were not implemented despite awareness of the problem.

Opinion M-37050 clarifies that incidental take is not a violation of the MBTA.  However, this federal Opinion does not supersede other protections for bird’s and their nests.  It is very important to note that the MBTA is just one facet of a protective framework for wild birds in California.  The California Fish and Game Code (CFGC) provides broadly similar protections (most specifically codes 3503, 3503.5, and 3513). Similar to the MBTA, there has been ambiguity on the applicability of these restrictions to incidental actions.  A California Supreme Court case determined the CDFW has legal control over incidental take for threatened, endangered, and fully protected animals.  It is not clear if this expanded definition of take applies to non-status bird species, but the advisory issued on November 29, 2018, counsels that the prohibition on incidental take applies to all sections of CFGC.  Per CFGC section 3503, it is unlawful to “take, possess, or needlessly destroy the nest or eggs of any bird.”

Key Factors

WRA clients and teaming partners should be aware of the following:

  • Opinion M-37050 will likely not be the final word on this topic from the DOI. Strong criticism from environmental groups and others (including former DOI employees) has been articulated and the issue will very likely remain contested and subject to re-interpretation.  Eight states including California, have filed a lawsuit on the “abandonment” of migratory bird protections outlined in Opinion M-37050.
  • CFGC section 3503 protects active nests and compliance with this and other sections of the CFGC is expected.
  • All existing permit measures, California Environmental Quality Act (CEQA) Mitigation Measures, and other requirements for various actions that stipulate nesting bird avoidance are not rendered invalid by Opinion M-37050; compliance is still expected.
  • Measures protecting nesting birds/active nests remain common in California. For example, permits and authorizations from the CDFW such as Streambed Alteration Agreements and Incidental Take Permits do not rely on the MBTA for the basis of bird protection, and will likely continue to include such measures.


WRA’s general recommendations regarding bird/nest avoidance remain essentially unchanged.  The most effective method of avoiding impacts to nesting birds (or even simply the perception that birds have been impacted) is to perform the removal of trees and other vegetation from September 1 through January 31, outside of the greater nesting bird season as is typically defined by CDFW.  If such is not feasible, pre-construction surveys by a qualified biologist and subsequent avoidance of any active nests found are strongly recommended, particularly for larger-scale actions with an associated higher likelihood of impact.

WRA biologists have a tremendous amount of experience with nesting bird avoidance and related compliance issues.  If nesting bird surveys are required for your action or if you simply have questions about your obligation to avoid any such impacts, please contact us.