We found that larger predators often left no sign, an avian predator completely destroyed a nest, disturbance by ground squirrels varied from one extreme to the other, and ground squirrels left circular holes in three nests. Such intraspecific variability and interspecific overlap in types of sign indicate that evidence at the nest is not a reliable basis for predator identification. Clay-colored sparrow bringing food to nestlings. Documenting Nest Activities Videotapes of nests were useful for determining incubation and brooding patterns and parental visitation rates. Video image quality also limited our ability to identify food items.
Savannah sparrow eating the shell from the first hatched egg.
Male chestnut-collared longspur giving food to the female, who then feeds the nestlings. Two cameras failed because their housings were not watertight. Cable connectors occasionally developed electrical shorts. Near the end of the 1997 season, all cables connecting cameras to VCRs were severely chewed, apparently by rodents. No VCR or tape failures occurred.