Patterns of Distribution and Abundance of Breeding Colonial Waterbirds in the Interior of California, 2009–2012 1 November 2014 Report to: California Department of Fish and Wildlife Wildlife Branch – Nongame Wildlife Program 1812 9th Street Sacramento, CA 95811 and U.S. Fish and Wildlife Service, Region 8 Migratory Bird Program 2800 Cottage Way Sacramento, CA 95825 W. David Shuford Point Blue Conservation Science 3820 Cypress Drive # 11 Petaluma, CA 94954 Author contact information: W. David Shuford Point Blue Conservation Science 3820 Cypress Drive #11 Petaluma, CA 94954 [email protected] www.pointblue.org Cover photo: Multi-species colony, dominated by American White Pelicans (Pelecanus erythrorhynchos) and Ring- billed and California gulls (Larus delawarensis and L. californicus), on a large rocky islet in the east lobe of Clear Lake National Wildlife Refuge, Modoc County, California. Photo, 18 May 2009, by the author. Recommended citation: Shuford, W. D. 2014. Patterns of distribution and abundance of breeding colonial waterbirds in the interior of California, 2009–2012. A report of Point Blue Conservation Science to California Department of Fish and Wildlife and U.S. Fish and Wildlife Service (Region 8). Available at www.fws.gov/mountain- prairie/species/birds/western_colonial/. CONTENTS Acknowledgments…………………………………………………………………………………v Executive Summary…………………………………………………………………………….…1 Introduction………………………………………………………………………………………..3 Study Area and Methods…………………………………………………………………………..4 Background and Overall Approach…………………………………………………….….4 Estimating Regional and Statewide Population Estimates…………………………….…..6 Survey Protocols………………………………………………………………………......7 Northeastern California: 2009……………………………………………………………..8 Pelicans and Cormorants…………………………………………………………..9 Herons and Egrets………………………………………………………………..10 Ring-billed and California Gulls…………………………………………………12 Franklin’s Gulls…………………………………………………………………..15 Caspian Terns…………………………………………………………………….15 Northeastern California: 2010……………………………………………………………16 Black Terns……………………………………………………………………....17 Forster’s Terns…………………………………………………………………...18 Eared Grebes……………………………………………………………………..19 White-faced Ibis………………………………………………………………….19 Egrets and Night-Herons…………………………………………………………20 Central Valley: 2010……………………………………………………………………..20 Black Terns………………………………………………………………………21 Sacramento Valley and Delta: 2011……………………………………………………...22 Cormorants, Herons, Egrets, Night-Herons………………………………………22 Northern and Central Coast: 2011………………………………………………………..25 Cormorants, Herons, Egrets, Night-Herons………………………………………25 San Joaquin Valley: 2012………………………………………………………………...26 Cormorants, Herons, Egrets, Night-Herons………………………………………26 Eared Grebes and Terns…………………………………………………………..27 Southern Coast: 2012…………………………………………………………………….27 Cormorants, Herons, Egrets, Night-Herons………………………………………28 Terns and Skimmers……………………………………………………………...28 Salton Sea and Imperial Valley: 2012…………………………………………………….28 Cormorants, Herons, Egrets, Night-Herons………………………………………29 Gulls, Terns, Skimmers…………………………………………………………..31 Lower Colorado River, Mojave River, and Owens River Valleys: 2012…………………31 Cormorants, Herons, Egrets, Night-Herons………………………………………31 Klamath River Country: 2012…………………………………………………………....32 Herons……………………………………………………………………………32 White-faced Ibis 2010–2012……………………………………………………..………33 Data Summary and Presentation………………………………………………………………....33 Ecoregions………………………………………………………………………………..34 Central Valley Joint Venture Regions……………………………………………….…..34 Mapping……………………………………………………………………………….…35 Results…………………………………………………………………………………………....35 Eared Grebe………………………………………………………………………………35 Double-crested Cormorant……………………………………………………………….35 American White Pelican……………………………………………………………….…36 Great Blue Heron…………………………………………………………………………36 Great Egret……………………………………………………………………………….37 Snowy Egret……………………………………………………………………………...37 Cattle Egret………………………………………………………………………………38 Black-crowned Night-Heron…………………………………………………………..…38 White-faced Ibis………………………………………………………………………….39 Franklin’s Gull………………………………………………………………………...…39 Ring-billed Gull and California Gull……………………………………………………..39 Caspian Tern……………………………………………………………………………..40 Black Tern……………………………………………………………………………..…42 Forster’s Tern…………………………………………………………………………….43 Other Species……………………………………………………….……………………43 Discussion………………………………………………………………………………………..43 Accuracy and Challenges of Counts……………………………………………………..43 Drought Conditions………………………………………………………………………47 Threats to Waterbirds…………………………………………………………………….48 Future Monitoring………………………………………………………………………..49 Literature Cited…………………………………………………………………………………..52 Appendix 1……………………………………………………………………………………….56 Tables…………………………………………………………………………………………….58 Figures…………………………………………………………………………………………..114 ACKNOWLEDGMENTS For a project of this scope, it is difficult to properly acknowledge all of the varied contributions and to gauge their relative importance. It is clear, however, that the individual and organizational contributions were synergistic and their worth far greater than the sum of the parts. My debt to those who helped in any capacity, whether visible to me or not, is deep and wide, and I take responsibility for any contributors I may have inadvertently overlooked. The following individuals provided valuable information or advice, help on field surveys, data from their own surveys, logistical support, or access to private or restricted public lands, without which this study would not have been possible: Ken Able, Nancy Abreu, Brian Acord, Sara Acosta, Roger Adamson, Lindsay Adrean, Dan Airola, Jennifer Albright, Chris Allen, Heidi Allen, Larry W. Allen, Bob Altman, Elisabeth Ammon, Bert Anderson, Betina Anderson, Janica Anderson, Tom Anderson, Dominic Bachman, Norah Bain, S. Baldwin, Larry Ballard, Brad Bamwell, Bob Barnes, Joseph Barnett, Alan Barron, Bob Bathgate, Liz Bathgate, Bob Battagin, Dan Battaglia, Madeline Bauer, Don Baylis, Ruth Baylis, Laurie Bechtler, John Beckstrand, Ted Beedy, Christy Bengston, Dave Bengston, Eric Bernsten, Patti Blumin, Janet Bosshard, Justin Boster, Russ Bradley, Tammy Branston, Summer Brasuel, John Breckenridge, Joan Brenchley- Jackson, Jennifer Bruce, Steve Brueggemann, Sharon Burkett, Ryan Burnett, Dennis Buss, Denise Cadman, Art Carey, Wade Carlson, Tom Cashman, Ann Cassidy, Kathy Cecere, Jamie Chavez, Pam Cherny, David Christophel, Kirsten Christopherson, John Clark, Steve Clay, Bob Claypole, Matt Coleman, Marile Colindres, Dave Compton, Chris Conard, Emiko Condeso, Rosamonde Cook, Dan Cooper, Steve Cordes, Troy Corman, Charles Coston, Sean Cross, Richard Crowther, Nina D'Amore, Brian Daniels, Jeff Davis, Bill Deane, Bill Deppe, Jeana De La Torre, Jill Demers, Larita Desimpel, Lori Dieter, Ryan DiGaudio, Colin Dillingham, Rob Doster, Jim Dunn, Bob Dyer, Tom Edell, E. Eidson, Ray Ekstrom, Janeann Erickson, Susan Euing, Jules Evens, Mike Farmer, Lucie Faulquier, Dave Feliz, Francesca Ferrara, Melanie Findling, Binny Fischer, K. Fischer, Susie Fork, Jeanne Fouts, Ada Fowler, Scott Frazer, Kyri Freeman, Linda Freeman, Ruth Friedman, Matt Freis, Shawn Fresz, Wes Fritz, Cindy Fuog, René Fuog, Colene Gamble, Steve Gerow, Geoff Geupel, Karen Gilbert, Michelle Gilbert, Tony Gilbert, Kirk Gilligan, Beryl Glitz, Dohn Glitz, Alan Goggins, Greg Golet, Jessica Gonzalez, Frank Gray, Helen Green, Kelsey Green, Cory Gregory, Ann Greiner, Lori Griffin, Phil Gulley, David Haines, Dan C. Hair, Madelon Halpern, Robert A. Hamilton, Lauren Hammack, Steve v Hampton, Rob Hansen, Deyea Harper, John Harris, Lauren Harter, Floyd Hayes, Jo Heindel, Tom Heindel, Phil Henderson, Carlie Henneman, Kathy Henry, Katie Henry, Tim Hermansen, Robert W. Hewitt, Diane Hichwa, Catherine Hickey, Rod Higbie, Steve High, Bill Hill, Jan Hintermeister, Justin Hite, Joan Hoffman, Rob Holbrook, Eric Hopson, Jenny Hoskins, Roger Hothem, Debbie House, Chris Howard, Richard E. Hubacek, Joan Humphrey, Diana Humple, John E. Hunter, Ryan Hurley, Karen Hussey, Carole Hutchinson, Jennifer Isola, Barbara Iyer, Linda Johnson, Rick Johnson, Todd Johnson, Dennis Jongsomjit, Linda Jordan, Jaime Karaszewski, Beth Kean, Kathy Keane, Robert J. Keiffer, Robin Keister, Rebecca Kelley, John Kelly, Rebecca Kelly, Rodd Kelsey, Carolyn Kinet, Doug King, Don Kirker, Brian Knott, Dan Kopp, Ellen Krebs, Dean Kwasny, Keiller Kyle, Jessica LaCoss, Joan Lamphier, Brett Lane, Gary Langham, Steve Laymon, Paul Lehman, Amy Leist, Robin Leong, Beth Lesar, Doug Leslie, Ron LeValley, Eileen Libby, Gary Lindquist, Patricia Lindsey, Wayne Little, Nora Livingston, Henry Lomeli, Carolyn Longstreth, La Lor, Tim Ludwick, David Lukas, Michael Mace, Chris McCreedy, Paul MacGarvey, Clysta McLemore, Raleigh McLemore, John McNerney, Mike McVey, Mike Mammoser, Jane Manning, Larry Manning, Tim Manolis, Cindy Margulis, Jessica Marquis, Will Mashburn, Jean Matin, Dave Mauser, Bob Meese, Francine Mejia, Linda Melching, Mary Merriam, Peter J. Metropulos, Jean Miller, Sarah Millus, Kathy Molina, Bill Moramarco, Josh More, Jason Morgan, Stella Moss, Patricia Mull, Richard Mull, Brennan Mulrooney, Dan Murphy, Shannon Murphy, Shirley Murphy, Steve Myers, Kristie Nelson, Len Nelson, Fran Neves, Wally Neville, Jeff Nordin, Kit Novick, Kimberly Oldehoeft, Elissa Olimpi, Theresa Olson, Lew Oring, William Owens, Gary Page, Seth Paine, Elizabeth Palmer, Ed Pandolfino, Debby Parker, Jim Parker, Sharon Parker, Jim Pea, Gayle Pena, Linda Perkins, Shawn Petrash, Allison Pierce, Jim Pike, Linda Pittman, Michael Prather, Lin Priest, Brian Prochazka, Bernadette Ramer, Bob Ramer, John Ranlett,