Figure 6b. Bald Eagle Christmas Bird Count Data

Iowa Mid-Winter Bald Eagle Iowa Mid-Winter Bald Eagle SurveySurvey

Several thousand eagles spend their winters Several thousand eagles spend their winters in Iowa, a significant portion of the lower 48 in Iowa, a significant portion of the lower 48

states’ population. states’ population.

0

500

1000

1500

2000

2500

3000

3500

4000

4500

2001 2003 2005 2007 2009 2011

number of eagles

Incidence of Abnormal Lead Levels in Incidence of Abnormal Lead Levels in Bald Eagles admitted to Iowa Wildlife Bald Eagles admitted to Iowa Wildlife

RehabilitatorsRehabilitatorsJanuary 2004 thru March 2011January 2004 thru March 2011

0

5

10

15

20

25

30

35

40

2004 2006 2008 2010

total admitted

# tested for lead

# showingabnormal leadlevels

Eagles admitted with abnormal Eagles admitted with abnormal lead levels - by the month -lead levels - by the month -

January 2004 thru March 2011January 2004 thru March 2011

0

10

20

30

40

50

60

total admitted to rehabilitators showing lead poisoning or exposure

Year Total # 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

20042004 88 5 (62.5%)5 (62.5%) 00 33 37.5%37.5%

20052005 2020 18 (90.0%)18 (90.0%) 11 1313 70.0%70.0%

20062006 2020 11 (55.0%)11 (55.0%) 22 77 45.0%45.0%

20072007 2323 17 (73.9%)17 (73.9%) 22 1111 56.5%56.5%

20082008 2121 17 (80.9%)17 (80.9%) 22 99 52.4%52.4%

20092009 3939 36 (92.3%)36 (92.3%) 66 2121 69.2%69.2%

20102010 2323 18 (78.3%)18 (78.3%) 55 44 39.1%39.1%

2011 2011 (thru (thru March)March)

1616 9 (56.3%)9 (56.3%) 22 44 37.5%37.5%

TOTALTOTAL 170170 131131 2020 7272 54.1%54.1%

Unsustainable mortality Unsustainable mortality rate?rate? Using rehabilitation data as a sample, Using rehabilitation data as a sample,

eagles admitted from January 2004 thru eagles admitted from January 2004 thru March 2011; March 2011;

Lead ingestion accounts for over half of all Lead ingestion accounts for over half of all bald eagle mortalities, effectively doubling bald eagle mortalities, effectively doubling their mortality rate.their mortality rate.

When looking at entire data set (n=170), When looking at entire data set (n=170), without lead mortality, only 78 eagles without lead mortality, only 78 eagles would have been admitted for care vs. 170.would have been admitted for care vs. 170.

When looking at the sub sample of those When looking at the sub sample of those tested for lead (n=131), only 39 eagles tested for lead (n=131), only 39 eagles were admitted with known normal lead were admitted with known normal lead levels.levels.

Estimates of number of Estimates of number of eagles dying from lead in eagles dying from lead in

IowaIowaYearYear Number of Number of

Eagles Eagles Admitted Admitted with with Abnormal Abnormal Lead LevelsLead Levels

Estimate Estimate of Total of Total Eagle Eagle Deaths Deaths due to due to Lead Lead Ingestion Ingestion

20042004 33 2020

20052005 1414 9393

20062006 99 6060

20072007 1313 8787

20082008 1111 7373

20092009 2727 180180

20102010 99 6060

TOTALTOTALSS

8686 573573

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.

After spending over 30 years on the After spending over 30 years on the Endangered/Threatened List, Bald Endangered/Threatened List, Bald

Eagles are still listed as a species of Eagles are still listed as a species of Special Concern and as a Species of Special Concern and as a Species of Greatest Conservation Need in IowaGreatest Conservation Need in Iowa

050,000

100,000150,000200,000250,000300,000350,000400,000450,000500,000

pre-settlement

1960s -DDT

2009

number of eagles

Most eagles admitted with lead in their Most eagles admitted with lead in their systems do not survive,systems do not survive,

of 86 only 6 were able to be released of 86 only 6 were able to be released (7%).(7%).

Preventable poisoning is Preventable poisoning is not an acceptable form of not an acceptable form of

mortalitymortality