Microorganisms, Bacteria and Viruses. Microbiological contamination of water has long been a concern to the public. From the 1920's-1960's, the bacillus which causes typhoid fever was considered a major problem in the water supply (1). Once it was eradicated, new microbes were present to take its place.
How long does a mourning dove sit on her eggs for them to hatch? Robins keep the clutch cool before the last egg is laid so the nestlings all hatch at approximately the same time. Incubating is done mainly by the female, who rarely leaves her clutch for more than a few minutes at a time.
Rating Newest Oldest. Best Answer: An American Robin lays 3-7 eggs. They hatch in approximately 12-14 days, and the babies fledge (leave the nest) when they are about 14-16 days old. Baby birds do not know how to fly when they leave the nest. They spend several days hopping around on the ground and climbing low branches until their wings are strong enough for flight.