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Ecology, management and conservation in natural and modified habitats
RESEARCH ARTICLE

Use of DiazaCon™ as a reproductive inhibitor for monk parakeets (Myiopsitta monachus)

Christi A. Yoder A C , Michael L. Avery B , Kandy L. Keacher B and Eric A. Tillman B
+ Author Affiliations
- Author Affiliations

A USDA/APHIS/WS/National Wildlife Research Center, 4101 LaPorte Avenue, Fort Collins, CO 80521, USA.

B USDA/APHIS/WS/National Wildlife Research Center, 2820 East University Avenue, Gainesville, FL 32641, USA.

C Corresponding author. Email: christi.yoder@aphis.usda.gov

Wildlife Research 34(1) 8-13 https://doi.org/10.1071/WR06069
Submitted: 8 June 2006  Accepted: 30 January 2007   Published: 27 February 2007

Abstract

Feral monk parakeet (Myiopsitta monachus) populations have become established in the United States and other countries around the world, and can cause damage to electrical facilities. Because the monk parakeet is a highly visible species and there is often public opposition to lethal control measures, non-lethal methods, such as contraception, are being developed to help control the spread of feral populations. Two gavage studies and one ad libitum nesting study were conducted to assess the efficacy of DiazaCon™ as a potential contraceptive for the monk parakeet. The first gavage study compared daily dose levels of 0, 50, 75, and 100 mg DiazaCon™ (kg bodyweight)–1 administered for 10 consecutive days. Cholesterol concentrations decreased significantly concomitant with a significant increase in desmosterol concentrations in the treated groups, but did not vary between sexes. Cholesterol and desmosterol concentrations did not differ significantly among DiazaCon™ groups, and cholesterol remained significantly suppressed 12 weeks after treatment. On the basis of these results, the second gavage study compared 5 or 10 consecutive days of DiazaCon™ administration at 50 mg kg–1 bird–1 day–1. Cholesterol concentrations decreased significantly concomitant with a significant increase in desmosterol concentrations in the treated groups, but did not vary between sexes. Cholesterol and desmosterol concentrations did not differ significantly between DiazaCon™ groups, and cholesterol remained significantly suppressed 11 weeks after treatment. Parakeets in the nesting study were fed hulled sunflower seeds treated with a target dose of 50 mg DiazaCon™ kg–1 bird–1 day–1. Birds consumed enough to receive an average dose of 34 mg kg–1 pair–1 day–1, or 17 mg kg–1 bird–1 day–1. Birds in the treated group laid an average of 1.6 ± 0.7 eggs per clutch compared with 3.9 ± 1.1 eggs per clutch in the untreated control group. None of the eggs laid by treated birds hatched compared with 1.1 ± 0.6 eggs per clutch hatching in the control group. Reproductive inhibition was effective for the length of the breeding season, at which time the study was stopped and no more data were collected. DiazaCon™ is a promising avian oral contraceptive that should be further investigated in a field setting with monk parakeets.


References

Ashraf, J. , Feix, J. B. , and Butterfield, D. A. (1984). Membrane fluidity and myotonia: effects of cholesterol and desmosterol on erythrocyte membrane fluidity in rats with 20,25-diazacholesterol-induced myotonia and on phospholipids liposomes. Bioscience Reports 4, 115–120.
Crossref | GoogleScholarGoogle Scholar | PubMed | Bump G. (1971). The South American monk, quaker, or gray-headed parakeet. Wildlife Leaflet 496. United States Fish and Wildlife Service.

Butterfield, D. A. , and Watson, W. E. (1977). Electron spin resonance studies of an animal model of human congenital myotonia: increased erythrocyte membrane fluidity in rats with 20,25-diazacholesterol-induced myotonia. Journal of Membrane Biology 32, 165–176.
Crossref | GoogleScholarGoogle Scholar | PubMed | Godoy J. C. (1963). Fauna Silvestre. Consigo Federal de Inversiones Buenos Aires, Argentina.

Griffiths, R. G. , Double, M. C. , Orr, K. , and Dawson, R. J. G. (1998). A DNA test to sex most birds. Molecular Ecology 7, 1071–1075.
Crossref | GoogleScholarGoogle Scholar | PubMed | Powell J. E. (1966). The effects of 20,25 diazacholesterol dihydrochloride (SC-12937) on the fecundity of the Japanese quail and parakeets. M.Sc. Thesis, University of Massachusetts, Amherst, MA, USA.

Pruett-Jones, S. , and Tarvin, K. A. (1998). Monk parakeets in the United States: population growth and regional patterns of distribution. Proceedings of the Vertebrate Pest Conference 18, 55–58.
SAS Institute Inc (2003). ‘SAS. Version 9.1.’ (SAS Institute Inc.: Cary, NC.)

Spreyer M. F., and Bucher E. H. (1998). Monk parakeet (Myiopsitta monachus). In ‘The Birds of North America, No. 322’. (Eds A. Poole and F. Gill.) (The Birds of North America, Inc: Philadelphia, PA.)

Stout, R. J. , Knuth, B. A. , and Curtis, P. D. (1997). Preferences of suburban landowners for deer management techniques: a step towards better communication. Wildlife Society Bulletin 25, 348–359.
Tillman E. A., van Doorn A., and Avery M. L. (2001). Bird damage to tropical fruit in south Florida. In ‘Proceedings of the Ninth Wildlife Damage Management Conference’. pp. 47–59.

Tillman, E. A. , Genchi, A. C. , Lindsay, J. R. , Newman, J. R. , and Avery, M. L. (2004). Evaluation of trapping to reduce monk parakeet populations at electric utility facilities. Proceedings of the Vertebrate Pest Conference 21, 123–129.
van Doorn A. (1997). Factors influencing success and population trends of introduced parrots in Florida. M.Sc. Thesis, University of Florida.

Yates, R. D. , Chen, I.-L. , and Mascorro, J. A. (1968). Some morphological effects of 20,25-diazacholesterol (SC-12937) on adrenocortical cells of the Syrian hamster. Texas Reports on Biology and Medicine 26, 241–248.
PubMed |

Yoder, C. A. , Andelt, W. F. , Miller, L. A. , Johnston, J. J. , and Goodall, M. J. (2004). Effectiveness of twenty, twenty-five diazacholesterol, avian gonadotropin-releasing hormone, and chicken riboflavin carrier protein for inhibiting reproduction in Coturnix quail. Poultry Science 83, 234–244.
PubMed |