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Name: Rob
Location: N/A
Country: N/A
Date: 8/12/99 


Question:
We live adjacent to the Deer Grove Forest Preserve of Cook County, Illinois. While pruning our bushes this past weekend I found a bird's nest with three eggs in one of the bushes. I figured they were abandonded after the Spring breeding season, but later in the day I noticed the tailfeathers of a full-grown bird protruding from the nest. I believe it is a Cardinal's nest due to the sighting and the sounds of both a male (red) and a female in the adjacent tree as I was pruning. I'd only hear her calls when I was near the bush. Apparently, I flushed her out as I bothered the bush. I thought common, Northern birds breed in the Spring to allow enough time for their young to grow and strengthen for the Fall migration. How long is their breeding period? How long is the maturation period of the eggs? Isn't this kinda late in the year, in Cook County, Illinois, for birds to lay eggs? I appreciate your response, Rob



Replies:
Smaller songbirds of our region often raise two broods a year, and some, like cardinals, may attempt a third. The odds of the young surviving go down for each later nesting but there is always a chance of raising more young and in the highly competitive natural world, every chance is grabbed at. Non-migratory birds like cardinals are more likely to nest late in the summer than migratory species. I have seen birds on nests as late as September but I wonder what the odds of success of those are. The nesting phase is surprisingly short, once incubation starts it takes 10 to 12 days for hatching and about another 2 weeks to flight, then the young have a pretty good chance of survival.

John Elliott


Hi Rob,

As a Cook County Resident myself and an avid birdwatcher, I can attest to the fact that nests are active well into the summer. Many bird pairs will raise more than one successful cluches. Cardinals are known to nest more than once, but most do not nest this late in the season, unless their first attempts were unsuccessful. One of the bigger problems in our area is the cowbird which lays its eggs in other species nests for them to raise. One of the cardinal pairs near me this year raised a cowbird instead of their own young, which were kicked out of the nest by the cowbird chick. What triggers a pair to raise young late in the year is not known, however, our growing season goes well into September and food is plentiful, so it may not be strange after all.

We have additional information on Cardinals on our Nature Bulletins. Use the search engine within NEWTONBBS to find them.
http://www.newton.dep.anl.gov

Steve



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