BEFORE THE CALIFORNIA FISH AND GAME COMMISSION A Petition to List the Tricolored Blackbird (Agelaius tricolor) as Endangered under the California Endangered Species Act and Request for Emergency Action to Protect the Species tricolor blackbird, Agelaius tricolor, Dave Menke, USFWS August 19, 2015 i Petition to list the Tricolored Blackbird as Endangered With Emergency Regulations Notice of Petition For action pursuant to Section 670.1, Title 14, California Code of Regulations (CCR) and Sections 2072 and 2073 of the Fish and Game Code relating to listing and delisting endangered and threatened species of plants and animals. I. SPECIES BEING PETITIONED: Common Name: Tricolored Blackbird (Agelaius tricolor) II. RECOMMENDED ACTION: Immediate Listing as Endangered with Emergency Regulations The Center for Biological Diversity submits this petition to list the Tricolored Blackbird (Agelaius tricolor) as endangered throughout its range in California, under the California Endangered Species Act (California Fish and Game Code §§ 2050 et seq., “CESA”). This petition demonstrates that the Tricolored Blackbird clearly warrants listing under CESA based on the factors specified in the statute. This petition provides identical information as contained in the Center’s 2014 petition with the addition of an addendum providing new research. III. AUTHORS OF PETITION: Name: Lisa Belenky, Senior Attorney, Center for Biological Diversity, and Monica Bond, Wild Nature Institute Address: 1212 Broadway, Suite 800, Oakland, CA 94612 Phone: 510-844-7107 Fax: 415‐436‐9683 Email: [email protected] I hereby certify that, to the best of my knowledge, all statements made in this petition are true and complete. Signature: _________________ Date: August 19, 2015 August 19, 2015 ii Petition to list the Tricolored Blackbird as Endangered With Emergency Regulations Table of Contents Executive Summary .........................................................................................................................1 Procedural History ...........................................................................................................................4 The CESA Listing Process and Standard for Acceptance of a Petition ...........................................5 1.0 Population Status and Trend ......................................................................................................6 1.1 Historical Population Estimates ...................................................................................8 1.2 Recent Population Estimates......................................................................................11 1.3 Summary ....................................................................................................................13 2.0. Range and Distribution ..........................................................................................................17 2.1 Species’ Range ...........................................................................................................17 2.2 Historical Distribution ...............................................................................................19 2.3 Current Distribution ...................................................................................................20 3.0 Abundance ...............................................................................................................................23 3.1 Historical Abundance.................................................................................................23 3.2 Current Abundance ...................................................................................................24 4.0 Life History ............................................................................................................................25 4.1 Species Description ....................................................................................................26 4.2 Taxonomy and Population Genetics ..........................................................................27 4.3 Reproduction and Growth ..........................................................................................28 4.4 Diet and Foraging Ecology ........................................................................................28 4.5 Mortality and Population Regulation .........................................................................30 5.0 Kind of Habitat Necessary for Survival .................................................................................30 6.0 Factors Affecting the Ability to Survive and Reproduce .......................................................36 6.1 Present or Threatened Destruction, Modification, or Curtailment of Habitat or Range ....................................................................................................37 August 19, 2015 iii Petition to list the Tricolored Blackbird as Endangered With Emergency Regulations 6.1.1 Destruction of Native Habitats ....................................................................37 6.1.2 Colony Destruction by Agricultural Activities ...........................................38 6.1.3 Destruction of Other Suitable Upland Breeding Substrates and Surrounding Habitats ................................................................................41 6.2 Inadequacy of Existing Regulatory Mechanisms ......................................................41 6.3 Overutilization for Commercial, Recreational, Scientific, or Educational Purposes 42 6.4 Disease or Predation ..................................................................................................42 6.5 Other Natural or Anthropogenic Factors ...................................................................44 6.5.1 Storms and Droughts..................................................................................44 6.5.2 Poisons and Contaminants .........................................................................45 6.5.3 Killing Blackbirds for Crop Protection ......................................................47 6.5.4 Allee Effect of Small Population Size .......................................................48 7.0 Degree and Immediacy of Threat and Request for Emergency Action ................................49 7.1 Degree and Immediacy of the Threat...........................................................................49 7.2 Request for Emergency Action ....................................................................................50 8.0 Impacts of Existing Management Efforts ...............................................................................50 8.1 Silage Buy-outs and Harvest Delays..........................................................................50 8.2 Tricolored Blackbird Working Group and Conservation Plan ..................................53 9.0 Recommended Future Management and Recovery Actions .................................................54 10.0 Availability and Sources of Information ..............................................................................57 11.0 Detailed Distribution Map ...................................................................................................61 August 19, 2015 iv Petition to list the Tricolored Blackbird as Endangered With Emergency Regulations Executive Summary The Tricolored Blackbird (“Tricolor;” Agelaius tricolor) is a colonial-nesting passerine largely endemic to California. It forms the largest colonies of any passerine in North America since the extinction of the Passenger Pigeon (Ectopistes migratorius, Bent 1958). Colonially nesting birds are particularly vulnerable to extinction because a small number of colonies can include a large proportion of the population; thus human activities can have catastrophic effects by killing adults or chicks or destroying habitat (Cook and Toft 2005). Such was the fate of the colonial Passenger Pigeon, Carolina Parakeet (Conuropsis carolinensis), and Great Auk (Pinguinus impennis) and will be the fate of the Tricolored Blackbird if immediate action is not taken. As scientists working with the Tricolored Blackbird noted, early actions are needed to protect colonial bird species from rapid collapse. “Surely the legacy of Passenger Pigeon should be our understanding of how such extinctions can occur rapidly in extremely abundant organisms because of non-linear population dynamics and thresholds caused by inverse density dependence. Failure to address the impact of habitat and human activities on reproductive success of Tricolored Blackbird may again lead to the extinction of a once-abundant bird.” (Cook and Toft 2005:86.) Tricolored blackbird populations are declining at an alarming rate in large part due to the direct loss and degradation of habitat from human activities. This includes historical market hunting of blackbirds, poisonings and shootings to protect crops from blackbirds, pesticide use, and harvest of grain crops grown for dairy silage and other agricultural grain crops and routine plowing of weedy fields throughout most of its range during nesting season. For example, every year, thousands of Tricolors, often entire colonies of tens of thousands of birds representing the largest known colonies in a given year, nest unsuccessfully on agricultural lands because their eggs and nests are destroyed during harvest or weed abatement activities (Beedy and Hamilton 1999, Hamilton 2004, Cook and Toft 2005, Meese 2006, 2007, 2008, 2009a, 2011). The concentration of most of the known Tricolor