Movements, Nesting, and Response to Anthropogenic Disturbance of Marbled Murrelets (Brachyramphus marmoratus) in Redwood National and State Parks, California By: Percy N. Hébert and Richard T. Golightly Humboldt State University Department of Wildlife Arcata, California 95521 May 2006 California Department of Fish and Game, Habitat Conservation Planning Branch Species Conservation and Recovery Program Report: 2006-02. California Department of Transportation Report Number: F/CA/IR-2006/04. STATE OF CALIFORNIA DEPARTMENT OF TRANSPORTATION TECHNICAL REPORT DOCUMENTATION PAGE TR0003 (REV. 10/98) 1. REPORT NUMBER 2. GOVERNMENT ASSOCIATION NUMBER 3. RECIPIENT’S CATALOG NUMBER FHWA/CA/IR-2006/04 4. TITLE AND SUBTITLE 5. REPORT DATE Movements, Nesting, and Response to Anthropogenic Disturbance of May 2006 Marbled Murrelets (Brachyramphus marmoratus) in Redwood National and State Parks, California 6. PERFORMING ORGANIZATION CODE 7. AUTHOR(S) 8. PERFORMING ORGANIZATION REPORT NO. Percy N. Hébert and Richard T. Golightly 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. WORK UNIT NUMBER Humboldt State University Department of Wildlife Arcata, California 95521 11. CONTRACT OR GRANT NUMBER 43A0068.41 12. SPONSORING AGENCY AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED Final Report California Department of Transportation Sacramento, CA 95819 14. SPONSORING AGENCY CODE 15. SUPPLEMENTAL NOTES This is the final report for project F2002IR13 Evaluation of Human-caused Disturbance of Breeding Marbled Murrelets. Additional sponsors and funding partners in the marbled murrelet study were: U.S. Geological Survey Research Work Order # 70 National Park Service Agreement # J8480020013 California Department of Fish and Game Contract # P0185402 California Department of Parks and Recreation Contract # C0237020 California Department of Parks and Recreation Contract # C0037046 U.S. Bureau of Land Management Agreement # BAA010013-004 16. ABSTRACT During three nesting seasons a total of 102 marbled murrelets (Brachyramphus marmoratus) were captured on the ocean off northern California and had radio transmitters attached. Reproductive success varied between years, and the average reproductive success was 6.9-13.5%, depending on assumptions in the calculations. Most nest failures occurred early in incubation. Predation by corvids was implicated as a major source of nest failure. When nests were exposed to disturbance in form of sound from an operating chainsaw, neither incubating adults or chicks flushed from the nest. The proportion of resting behavior was significantly less when the saw was operating than before or after. Reproductive success was not reduced when nests were exposed to the sound disturbance. No correlation was found between nest success and distance from roads or trails. However, there was a potential for indirect effects of longer-term noise (greater than 15 minutes) due to potential attraction of corvids. Murrelets that were feeding chicks flew inland later in the morning than other inland flying murrelets. Only chick-feeding murrelets flew inland in the evening. Murrelets whose breeding attempts failed still continued to fly inland. At one nest equipped with a persistent video, murrelets nested at the same location on the platform for five years, but lost their eggs to Steller’s Jays or Ravens in 3 of 5 years. 17. KEY WORDS 18. DISTRIBUTION STATEMENT Marbled Murrelet, Disturbance, Nesting, Reproduction, Video, No restrictions. This document is available to the public through the Telemetry, Corvids. National Technical Information Service, Springfield, VA 22161 19. SECURITY CLASSIFICATION (of this report) 20. NUMBER OF PAGES 21. PRICE 339 Unclassified Reproduction of completed page authorized Movements, Nesting, and Response to Anthropogenic Disturbance of Marbled Murrelets (Brachyramphus marmoratus) in Redwood National and State Parks, California FINAL REPORT TO U.S. Geological Survey Research Work Order # 70 National Park Service Agreement # J8480020013 California Department of Fish and Game Contract # P0185402 California Department of Parks and Recreation Contract # C0237020 California Department of Parks and Recreation Contract # C0037046 California Department of Transportation Contract # 505-29-1 U.S. Bureau of Land Management Agreement # BAA010013-004 SUBMITTED BY Humboldt State University Sponsored Projects Foundation Arcata, California 95521 Principal Investigator: Richard T. Golightly Suggested Citation: Hébert, P. N. and R. T. Golightly. 2006. Movements, nesting, and response to anthropogenic disturbance of Marbled Murrelets (Brachyramphus marmoratus) in Redwood National and State Parks, California. Unpublished report, Department of Wildlife, Humboldt State University, Arcata, California and California Department of Fish and Game Report 2006-02, Sacramento, California. i TABLE OF CONTENTS Acknowledgements.................................................................................................................. vi Disclaimer..............................................................................................................................viii List of Tables ........................................................................................................................... ix List of Figures......................................................................................................................... xv Chapter 1: Evaluation of human-caused disturbance on the breeding success of Marbled Murrelets (Brachyramphus marmoratus) in Redwood National and State Parks, California ............................................................................................................................ 1 Methods............................................................................................................................. 7 Capture...................................................................................................................... 7 Handling Process ...................................................................................................... 7 Location of Nest Trees.............................................................................................. 8 Human-Disturbance at Nest Trees............................................................................ 9 Experimental Test of Human Disturbance.............................................................. 13 Nesting Success ...................................................................................................... 15 Statistical Analyses ................................................................................................. 17 Results............................................................................................................................. 18 Capture and Handling Process................................................................................ 18 Effects of Human Disturbance at Nest Trees.......................................................... 18 Experimental Human Disturbance.......................................................................... 22 Nesting Success ...................................................................................................... 28 Discussion....................................................................................................................... 30 Effects of Human Disturbance at Nest Trees.......................................................... 31 Experimental Human Disturbance.......................................................................... 35 Nesting Success ...................................................................................................... 37 Corvids.................................................................................................................... 38 Conclusion .............................................................................................................. 39 Literature Cited ............................................................................................................... 41 ii Chapter 2: Breeding biology of Marbled Murrelets (Brachyramphus marmoratus) nesting in Redwood National and State Parks, California................................................................. 69 Methods........................................................................................................................... 74 Capture.................................................................................................................... 74 Handling Process .................................................................................................... 75 Location of Nests .................................................................................................... 76 Morphology............................................................................................................. 77 Nesting .................................................................................................................... 77 Statistical Analyses ................................................................................................. 82 Results............................................................................................................................. 82 Morphology............................................................................................................. 82 Nesting .................................................................................................................... 83 Nesting Success