Survival
In adult House Sparrows, annual survival is 45-65%. After fledging and leaving the care of their parents, young sparrows have a high mortality rate, which lessens as they grow older and more experienced. Only about 20–25% of birds hatched survive to their first breeding season. The oldest known wild House Sparrow lived for nearly two decades; it was found dead 19 years and 9 months after it was ringed in Denmark. The oldest recorded captive House Sparrow lived for 23 years. The typical ratio of males to females in a population is uncertain due to problems in collecting data, but a very slight preponderance of males at all ages is usual.
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Famous quotes containing the word survival:
“We never stop investigating. We are never satisfied that we know enough to get by. Every question we answer leads on to another question. This has become the greatest survival trick of our species.”
—Desmond Morris (b. 1928)
“The planet’s survival has become so uncertain that any effort, any thought that presupposes an assured future amounts to a mad gamble.”
—Elias Canetti (b. 1905)