|
Long-term Monitoring of DDE and Other Organochlorine Contaminants in Spring Migrant Peregrine Falcons at Padre Island, Texas, 1978-2004
Active
This study continues work started in 1976 to analyze blood from Peregrine Falcons for evidence of toxic organochlorine pesticides such as DDE, a breakdown product of DDT. Peregrine Falcons suffered population declines in much of the northern hemisphere that were coincident with the use of DDT and resultant decreases in eggshell thickness. The Arctic subspecies, Falco peregrinus tundrius, migrates through Texas twice a year, stopping to feed before continuing their migration between the breeding grounds in the Arctic and wintering areas in South America. Capturing birds at Padre Island, Texas rather than in the Arctic offers several advantages. There is a higher density of birds, field costs are lower, and previous studies have shown that birds captured here represent broad geographical regions and have similar blood concentrations of organochlorines to those captured elsewhere. Blood samples were collected and analyzed in 1978-79, 1980, 1984, and 1994. Levels of DDE declined in 1984 and in 1994, below the level known to adversely affect the Arctic population’s productivity. Other studies have documented dramatic increases in Arctic Peregrine populations in the 1980s, and the species was removed from the USFWS list of threatened and endangered species in 1994. The decrease of organochlorine pesticides is encouraging, because burdens in this long-distance migrant reflect the condition of the environment in both North and South America. Blood samples were collected in 2004, but were not analyzed. The current study will analyze these samples, adding to the systematic long-term set of contaminants in the Arctic population during the post-delisting period.
Capture and collect blood samples from 27 adult female peregrines in the spring of 2004 and evaluate long-term residue trends of organochlorine contaminants in their plasma. This continues a long-term data set that began in 1978-79, with additional samples collected in 1980, 1984 and 1994.
The study was designed to further evaluate long-term DDE trends and other organochlorine contamination in plasma of spring migrant Peregrine Falcons (Falco peregrinus) making their first United States landfall on Padre Island, Texas, after spending the previous 6 months wintering throughout Latin America. A spring concentration of migrating peregrines was first discovered at Padre Island, Texas, in April 1978 by F.P. Ward (Hunt and Ward 1988, Henny et al. 1988). Padre Island peregrine habitat was described by Hunt and Ward (1988). Peregrines were captured with harnessed pigeons as in the past by trappers who have captured the falcons for many years at the Padre Island study site. Only 4 birds were captured in 1978, but techniques were improved, and 25 were captured in 1979 and 82 in 1980. Then, 43 were captured in 1984, and 70 in 1994. We collected blood from the brachial vein as described by Henny et al. (1982). A high percentage of the peregrines captured and bled were adult (after second year, ASY) females: 1978-79 (21), 1980 (63), 1984 (27), and 1994 (45). This study will utilize 27 adult females bled in the spring of 2004 under other non-USGS projects to extend the dataset another decade (1978-2004). The plasma samples have been stored frozen in an ultracold frozen (-80 C) and will be submitted for chemical analysis (same lab that analyzed all earlier samples).
Henny, C.J., Yates, M.A., Seegar, W.S., 2009, Dramatic declines of DDE and other organochlorines in spring migrant peregrine falcons from Padre Island, Texas, 1978-2004: Journal of Raptor Research, v. 43, no. 1, p. 37-42. [Highlight] [FullText] Catalog No: 2090
Fitzpatrick, Martin - Deputy Center Director
Phone: 541-750-1032
Email: Martin_Fitzpatrick@usgs.gov
 |
