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DDT affected the eggs and made the shells thin and weak. They broke when the mother eagle sat on them to hatch them.
According the the US Fish & Wildlife website DDT was the major contributing factor to Bald Eagle population decline after WWII, by 1963 there were only 487 nesting pairs left - that was the minimum population. Since DDT use was banned in the US in 1972 the population has rebounded even though there is increased loss of habitat & prey for them to feed on (esp. salmon).
The bald eagle population was just beginning to recover when a new threat emerged. The pesticide DDT, which was used to control insects that damaged crops, was getting into the food that the bald eagle ate. The pesticide made it more difficult for the bald eagle to absorb calcium and the lack of calcium made the shells of the bald eagle's eggs thinner. Many eggs broke before they could hatch and the bald eagle population dropped. DDT use was outlawed in the U.S. in 1972, and the bald eagle population has slowly recovered
Alternative answer:
A myth. DDT didn't affect Bald Eagle eggs. Bald Eagle populations reached their minimum in the US prior to the introduction of DDT(1940). Bald Eagle populations were already increasing by 1960 at the height of DDT production and usage.
The real cause of the Bald Eagle's decline was primarily hunting as they were considered a nuisance, a threat to livestock and the fisheries. Secondarily they suffered from a lack of food sources, habitat, poisoning from lead shot and other pollutants (lead, Mercury, etc.).
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One practice that has successfully increased the number of bald eagles in the US is?
The banning of the insecticide DDT is given much credit for the resurgence of eagles.DDT which the eagle got by eating animals that had eaten plantssprayed with DDT, caused eagle eggs to be defective, I forget exactly how.ans its answer is A. protection of their natural habitat.
Where do bald eagles make there home?
Bald eagles usually nest near large bodies of water, because of their preferred prey, fishes.
How many bald eagles are in the state of New Hampshire?
420
How many bald eagles are there in North America?
there are about 150,000 to 200,000.
Do bald eagles nest in the same nest every nest?
Bald eagles will return to the old nest, add new material, year after year, until the nest falls from its own weight. They then will construct a new one.
What caused bald eagles to be enangered?
from the bug killers DDT
How did bald eagles recover?
Elimination of the use of DDT as a pesticide.
Why are bald eagles indangered?
The bald eagle was endangered because of the use of DDT it weakened the shell of the eagles and they would break so the babies could not develop. DDT almost destroyed the bald eagle. Now since DDT has been banned the Bald eagle has made a great comeback.
What is one of the diseases that makes bald eagles die?
DDT was a pesticide that was used to kill bugs on farms. But when pretadors of those bugs were eaten by other predators the level of DDT rose and made the Bald Eagles egg shells very thin and usually the bald eagle would die. DDT is now outlawed, but the levels of DDT are still in fish and insects.
How did DDT enter the food chain?
DDT entered the food chain because it was in the water of the fish that bald eagles ate.
How did DDT not affect Eagles?
It did not improve their 'hatch-rate'.
How did the bald eagle die out?
DDT caused eggshells to be too brittle to hatch, and the eagles numbers plummeted..With the banning of DDT the population has rebounded to a point where they are no longer endangered.
What problems did buildup of DDT in adult bald eagles cause?
In the 1940-1950's, DDT was used on crops to control pests. The DDT entered the water and was absorbed into the food chain of the Eagle. DDT would then enter the Eagle's systemm and it would cause them to lay eggs that had weak shells. The shell would break before the eaglet had time to hatch, thus reducing the population and threatening their extinction.
How did they fix the bald eagle from being extinct?
The bald eagle was first protected in the US and Canada in 1918 and in 1940, the US made it illegal to trap and kill bald eagles. In 1967, the bald eagle was first listed as an endangered species. A few years later, the use of the pesticide DDT was banned in the US. DDT had been one of the big killers of the Bald Eagle. With the banning of DDT, the species began to rebound.
How did they become endangered?
because DDT fell into rivers in which fish sucked up and bald eagles eat the fish killing them
Are bald eagles almost extint?
The bald eagle was in decline because of now banned pesticides like DDT, but has made a remarkable comeback, and is now listed as "Least Concern".
Does bald eagle face extinction?
until DDT was banned the Bald Eagle did face extinction because the pesticide weakened the shell and when the parents would lay on the eggs it would break the shell.Now the bald eagle does not face extinction because they no longer use DDT eagles are making a wonderful comeback
