Science Art-Nature: What do you conclude when you find bodies in a nest box but have no forensic evidence to go on--no sign of disturbance, no obvious indications of parasitic infestation or disease?
One option is to check the recent weather records. Cold weather can reduce insect prey, leaving parents unable to provide sufficient food. Alternatively one or both parents could have died. If, however, the parents survived, then cleaning out the nest box might lead them to produce a replacement brood.
If that replacement brood successfully fledges, then the artist’s title, “A Perfect World” might refer to the time the young spent in the protective custody of their square box.
Interestingly, if it were a case of weather-related starvation, the male might well have been pale. It turns out that male Great Tits produce antioxidants, including yellow-producing carotenoid that both fight free radicals and give their breast feathers a yellow hue. Males with high levels of antioxidants produce sperm better able to withstand a free radical onslaught. In one study, stressed males had less resilient sperm and paler breasts. Thus, females choosing bright-breasted males appear to be choosing resilent sperm, as well. |
