Contents 



Page 



Contents iii 



Executive Summary vii 



Chapter 1. Natural history of the common murre (Una aalge califomica) 1 



Abstract 1 



Methods 3 



Overview of the biology of the common murre 4 



Reproductive ecology 5 



Breeding habitat 5 



Seasonal and daily colony attendance patterns 5 



Timing of breeding 7 



Egg laying 7 



Incubation and hatching 8 



Chick rearing and colony departure 8 



Demography 9 



Adult and subadult survival 9 



Proportion of adults that breed 9 



Hatching success 9 



Fledging success 10 



Breeding success 12 



At-sea chick rearing 13 



Philopatry, recruitment, and intercolony movements 14 



Colony formation and irregular attendance 14 



Predators 15 



Foraging ecology 16 



Diet 17 



At-sea distributions 18 



California 18 



Oregon 19 



Washington 19 



British Columbia 19 



Movements 20 



Acknowledgments 22 



Literature cited 22 



Additional references 30 



Unpublished data and personal communications 32 



Chapter 2. Population trends of the common murre (Una aalge califomica) 33 



Abstract 33 



Methods 36 



Summary of population data 38 



California 38 



Historical background on breeding colonies in California, 1800-1978 38 



Current population size and distribution of breeding colonies in California 39 



Population trends in central California, 1979-1995 42 



Population trends in northern California, 1979-1995 45 



Oregon 48 



Historical background on breeding colonies in Oregon, prior to 1980 48 



Current population size and distribution of breeding colonies in Oregon 51 



Population trends in Oregon. 1988-1995 52 



