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Figure 6b. Bald Eagle Christmas Bird Count Data. Iowa Mid-Winter Bald Eagle Survey Several thousand eagles spend their winters in Iowa, a significant.

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Presentation on theme: "Figure 6b. Bald Eagle Christmas Bird Count Data. Iowa Mid-Winter Bald Eagle Survey Several thousand eagles spend their winters in Iowa, a significant."— Presentation transcript:

1 Figure 6b. Bald Eagle Christmas Bird Count Data

2 Iowa Mid-Winter Bald Eagle Survey Several thousand eagles spend their winters in Iowa, a significant portion of the lower 48 states population.

3 Incidence of Abnormal Lead Levels in Bald Eagles admitted to Iowa Wildlife Rehabilitators January 2004 thru March 2011 Incidence of Abnormal Lead Levels in Bald Eagles admitted to Iowa Wildlife Rehabilitators January 2004 thru March 2011

4 Eagles admitted with abnormal lead levels - by the month - January 2004 thru March 2011

5 YearTotal # of eagles admitted to Iowa wildlife rehabilitators # tested for lead (% of total) # showing lead exposure # showing lead poisoning (lethal without treatment) % of total showing abnormal lead levels (62.5%) % (90.0%) % (55.0%) % (73.9%) % (80.9%) % (92.3%) % (78.3%) % 2011 (thru March) 16 9 (56.3%) % TOTAL %

6 Unsustainable mortality rate? Using rehabilitation data as a sample, eagles admitted from January 2004 thru March 2011; Using rehabilitation data as a sample, eagles admitted from January 2004 thru March 2011; Lead ingestion accounts for over half of all bald eagle mortalities, effectively doubling their mortality rate. Lead ingestion accounts for over half of all bald eagle mortalities, effectively doubling their mortality rate. When looking at entire data set (n=170), without lead mortality, only 78 eagles would have been admitted for care vs When looking at entire data set (n=170), without lead mortality, only 78 eagles would have been admitted for care vs When looking at the sub sample of those tested for lead (n=131), only 39 eagles were admitted with known normal lead levels. When looking at the sub sample of those tested for lead (n=131), only 39 eagles were admitted with known normal lead levels.

7 Estimates of number of eagles dying from lead in Iowa Year Number of Eagles Admitted with Abnormal Lead Levels Estimate of Total Eagle Deaths due to Lead Ingestion TOTALS86573 The number of eagles admitted to wildlife rehabilitators is only a portion of the eagles dying each year. Band return rates have been used to estimate the probability of the public finding an animal and reporting it (Green, personal communication). The band return rate for bald eagles is 15%. Number of eagles admitted with abnormal lead levels /.15 = Estimate of Total Eagle Deaths due to Lead Ingestion. On average, approximately 82 eagles are dying in Iowa each year due to lead ingestion.

8 After spending over 30 years on the Endangered/Threatened List, Bald Eagles are still listed as a species of Special Concern and as a Species of Greatest Conservation Need in Iowa

9 Most eagles admitted with lead in their systems do not survive, of 86 only 6 were able to be released (7%).

10 Preventable poisoning is not an acceptable form of mortality


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