Our yards, parks, woods, stream banks and other places where songbirds nest are teeming now with nestlings and fledglings. But I wonder how many of them — and how many of their parents — will be around next season.
Few wild birds die of old age. Most songbirds generally have less than a 25 percent chance of surviving their first year of life. Typical is the Northern cardinal’s plight. Because of threats such as parasitism from cowbirds and high predation by snakes, hawks and other creatures on eggs and nestlings, only 15 percent to 37 percent of cardinal nests produce fledglings, according to Birds of North America Online.
Life doesn’t get any easier for birds that survive to adulthood. Hazards such as predators, disease, outdoor cats, severe weather, starvation, pesticides, window collisions and habitat loss take a staggering toll on songbirds.
For migratory birds, the grueling long-distance treks they undertake each spring and fall present additional dangers. For small migratory birds such as warblers and vireos, average life expectancy may be only two years.
Larger, non-migratory birds may fare better. Based on life-expectancy studies of birds, the oldest American robins in our yards may be six years old. A Clemson University study found several 6- and 7-year old Eastern bluebirds living at various sites in Georgia and South Carolina.
But if a songbird survives predation, bad weather and all of the other vicissitudes that cause early demise, how long might it live until it succumbs to old age? Here are a few longevity records for some common birds: American robin (13.9 years); blue jay (16.3); Northern cardinal (15.7); ruby throated hummingbird (9); Eastern bluebird (10.5); Carolina chickadee (10.1); red-winged blackbird (15.3); tufted titmouse (13); downy woodpecker (11.9); Northern mockingbird (14.8).
IN THE SKY: From David Dundee, Tellus Science Museum astronomer: The moon will be last quarter on Friday. Venus is in the west just after dark and sets about two hours later. Mars rises in the east just before midnight and will appear near the moon tonight. Jupiter is high in the east, and Saturn rises in the east, around dusk. Earth reaches its farthest point from the sun — 95,059,750 miles away — at 1 p.m. on Friday.
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