Bird Life is a Hazardous Life!
By Dave Hanks
A bird’s life is fraught with problems. Of those individuals that are mature enough to migrate in the fall, only about a third of them are alive to return to their breeding grounds in the spring. But before that, young birds have tremendous obstacles to survive before they can be included in the fall migration numbers.
Around 60% of altricial (helpless) young born in open nests will hatch. One third of these will fledge. Cavity nesters have a better chance at life because the young are better protected and more mature before leaving the nest hole. About 75% will hatch and a little less than half will fledge. The period between leaving the nest, learning to feed oneself, and full flight is extremely perilous.
Precocial birds usually nest on the ground and only a third to a half of their eggs will reach hatching. Even though precocial chicks can run and feed themselves, they require parental protection. Many water bird young will be carried on their parent’s backs or under the adult’s wings.
The SONG SPARROW (pictured) is a generalist that will nest on the ground, in trees or in bushes. However, they do prefer brushy or marshy areas, even though they will nest in farming areas, along roadsides, and even in suburbia. This common bird can be recognized by its streaked breast and a large dot in the middle of its chest. It is a singer that lives up to its name.
Two thirds of Song Sparrow eggs hatch, half will fledge, but 80% will die before their first year is up, and only 10% will make it back to their breeding grounds.
Because bird life is so hazardous, heavy reproduction is necessary to maintain each species, as survival odds are not in their favor!
(A Song Sparrow bursting with song)
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