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:
“Evolution is the law of policies: Darwin said it, Socrates endorsed it, Cuvier proved it and established it for all time in his paper on “The Survival of the Fittest.” These are illustrious names, this is a mighty doctrine: nothing can ever remove it from its firm base, nothing dissolve it, but evolution.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)
“We hold on to hopes for next year every year in western Dakota: hoping that droughts will end; hoping that our crops won’t be hailed out in the few rainstorms that come; hoping that it won’t be too windy on the day we harvest, blowing away five bushels an acre; hoping ... that if we get a fair crop, we’ll be able to get a fair price for it. Sometimes survival is the only blessing that the terrifying angel of the Plains bestows.”
—Kathleen Norris (b. 1947)
“It is almost as if you were frantically constructing another world while the world that you live in dissolves beneath your feet, and that your survival depends on completing this construction at least one second before the old habitation collapses.”
—Tennessee Williams (1914–1983)