Avian nesting behavior

Avian nesting behavior permits investigation of contaminant effects on reproduction. Egg production, hatching success, nestling development, and survival are valuable endpoints to assess metal contamination effects on populations. High concentrations of cadmium may suppress egg production, and Cd and Pb have both been studied for risks of eggshell thinning 30, 99). 

Specifications for nest box placement and predator guards should also be included. Specifics of nest box placement will depend on the behavior of avian species being monitored. Inter-box distances and orientation to test areas are two parameters that may vary widely with the organism being smdied. Predators vary from area to area, and if nest boxes are near tree canopies, predation from above may in fact be the dominant route of predator intrusion rather than the standard access from the ground. 

Birds do not usually rely on scent for territorial marking. Some species, however, such as burrowing owls, apply odoriferous substances to their nest cavities or burrows. The functions are not well understood. Non-avian predators are thought to be the addressees, placing such marking outside the intraspecific behavior of this chapter. 

---