ABSTRACT
Body composition was measured in male American kestrels (Falco sparverius) beginning after a 77-day exposure to 0, 6, or 12 ppm (dry wt.) selenium as seleno-L-methionine in their diet. Total body mass, lean body mass, and body fat were compared among groups to identify potential wasting effects of selenium, as had been reported for wild waterfowl from a selenium-contaminated site. On the last day of selenium treatment, selenium concentrations in the blood of kestrels was significantly negatively correlated with lean mass. Kestrels that had been exposed to 12 ppm selenium in the diet exhibited relatively higher lean mass (relative to total body mass) and lower normalized body fat than kestrels fed 0 or 6 ppm dietary selenium. These differences persisted throughout the 6 mo study period. The effect observed on body condition of kestrels at environmentally relevant exposure levels has implications for wild birds with respect to both overwinter survival and reproductive success.
Subject(s)
Bird Diseases/chemically induced , Body Composition , Raptors/physiology , Selenium/toxicity , Animals , Bird Diseases/blood , Bird Diseases/pathology , Electric Conductivity , Female , Linear Models , Male , Random Allocation , Regression Analysis , Selenium/blood , Selenomethionine/administration & dosage , Spectrophotometry, Atomic/veterinary , Statistics, NonparametricSubject(s)
Animals, Wild , Databases, Factual , Ecology , Environmental Exposure , Animals , California , Ecosystem , Environmental Exposure/adverse effects , Environmental Exposure/analysis , Environmental Pollutants/toxicity , Environmental Pollution/prevention & control , Risk Assessment , Toxicity TestsSubject(s)
Columbidae , Diazinon/toxicity , Insecticides/toxicity , Organothiophosphorus Compounds/toxicity , Parathion/toxicity , Administration, Cutaneous , Administration, Oral , Animals , Cholinesterases/blood , Diazinon/administration & dosage , Dose-Response Relationship, Drug , Insecticides/administration & dosage , Organothiophosphorus Compounds/administration & dosage , Parathion/administration & dosageABSTRACT
To determine the relative contribution of mate access and environmental cues in stimulating egg-laying and plasma luteinizing hormone (LH) secretion in cockatiels (Nymphicus hollandicus), and of mate access on nest-inspection and bowl-formation, mated pairs were permitted different degrees of mate access (full contact, auditory plus visual contact, auditory contact only, or no contact) and sequentially exposed to three environmental conditions (8L:16D without nest-box access for 6 weeks; 15L:9D without nest-box access for 3 weeks; 15L:9D with nest-box access for 3 weeks). The results indicate that a high degree of mate access is essential for the performance of nesting behaviors, since birds allowed no mate access or only auditory mate access were significantly less likely to inspect the nest or form a nest-bowl. Furthermore, pairs permitted no contact, auditory contact only, or auditory and visual contact delayed nest-inspection and bowl-formation and were significantly less likely to lay eggs than pairs with total mate contact. LH levels were significantly elevated only in photostimulated females of pairs of permitted full mate and nest-box access. These results suggest that maximal sexual activity in cockatiels requires an array of behavioral and environmental cues and that a linear relationship exists between extent of social cues and sexual activity.
