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| Contaminant level in juveniles | |
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| Tweet Topic Started: Apr 10 2009, 11:36 PM (616 Views) | |
| dory | Apr 10 2009, 11:36 PM Post #1 |
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Advanced Member
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Dr. Sharpe Do you test the youngsters for contaminants? And how are their levels in comparison to the older eagles? Are the levels lessening with each generation? Thank you for taking the time to answer all our questions. Dory |
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| Eagle Guy | Apr 11 2009, 08:34 AM Post #2 |
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Advanced Member
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The contaminants increase with age of the bird. The 8-week-old chicks already have DDE contamination from the food brought ot the nest. |
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| ostrich2 | Apr 11 2009, 09:52 AM Post #3 |
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Advanced Member
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Dr. Sharpe, Is there then any data which could be gathered or any established research that would explain the successful hatchings (both least year at WE and this year at WE and TH). Are these successes considered indiciative of long term success in these birds, or could this still be a short-term anomaly? I gather the birds breeding on NCI have always been assumed to be able to breed because levels of physical contamination are lower there, and so far this has been borne out by sucessful hatchings. These all at a high level seem to associate egg laying and hatching success with levels of contamination in the adult birds (which may themselves start building up when they're eaglets). Since the WE birds are apparently the worst contaiminated as measured by levels in the blood, but are now breeding, does this suggest perhaps there are other possibly unknown factors that are important in the process and might explain success now when there has been failure in the many year before this? |
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| Eagle Guy | Apr 13 2009, 09:49 AM Post #4 |
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Advanced Member
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The problem with measuring DDE in eggs is that you can only do it if the egg doesn't hatch. Therefore it is difficult to make any direct conclusions about contaminant levels and hatching success. The purpose of the Santa Cruz project was to see if eagles could hatch successfully there, being further from the contaminant source. So far two pair have successfully hatched chicks. The thing is that the females are young, and in the case of the PH pair, fed on the mainland for a couple of years and then on feral pig for a year or two. Therefore, they would not have picked up much DDE. The Grassland female had also fed primarily on feral pig for the first few years of her life. The question now is whether they will eventually get levels of DDE that preclude successful breeding. The purpose of our continued monitoring and trapping efforts is to see if the birds are continuing to pick up additional contamination and whether they eventually fail at reproduction. |
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| lovethebabies | Apr 13 2009, 02:46 PM Post #5 |
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Advanced Member
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Thank you Dr. Sharpe for taking the time to answer all the questions. They are all questions that have been going through my mind too and I really appreciate having this portion of the forum to go to to see all your answers. Even when I don't have a question I find this area valuable but with the shocking, sad events at PH the past few weeks, I really value your input! You and your crew do such a fantastic job! I am very sad to lose PH again this year as this is the only cam I can get at work and I have watched it since that first year. I really love this pair and can't thank you enough for trying to answer all the questions! Keep up the great work and have a safe week! |
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4:56 PM Jul 10