NOTES 
Given the very large size and densities of the breeding colonies of terns on Isla 
Rasa — currently some 200,000 Elegant Terns and 14,000 Royal Terns (Velarde 
pers. obs.), the probability of finding one or a few Sandwich Terns on the island is 
low. But in view of the recent trend in the vagrancy of this species in western North 
America, more attention should be dedicated to the possibility of future sightings. 
Occurrence of the Sandwich Tern in the primary colony of the Elegant could lead to 
sporadic hybridization and the appearance of variably intermediate birds throughout 
the range of the Elegant. 
Research in Isla Rasa was jointly supported by the Fondo Mexicano para la Conser- 
vacion de la Naturaleza/Lindblad Expeditions/Packard Foundation Baja Forever fund 
during 2008 and by The Nature Conservancy International during 1986. Research 
permits were kindly issued by the Secretariat of the Environment, and the Mexican 
navy provided logistic support for transportation of research personnel. The manu- 
script was completed while Velarde was on sabbatical leave from the Universidad 
Veracruzana at the Biodiversity Research Center of the Californias of the San Diego 
Natural History Museum. We acknowledge the support received from Exequiel Ezcurra 
during this sabbatical. We also thank Philip Unitt, Michael W. Hager, and Margaret 
Dykens from the San Diego Natural History Museum. The manuscript was greatly 
improved by the reviews of Kathy Molina, Kimball Garrett, Ron LeValley, Charles 
Collins, and Philip Unitt. 
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