Chronology of Migration by American Coots in Oklahoma

Abstract

American coots (Fulica americana) were studied on large reservoirs in north-central Oklahoma in 1979-82 to determine chronologies of migrations by ageand sex class. Coots began migrating into Oklahoma in mid-September, numbers peaked in early to mid-October, and few birds were seen after 1 November. Some late migrants appeared in mid-December. In spring, coots began migrating in late February, numbers peaked in mid-April, and the last birds were seen in mid-May. Generally, adult and juvenile males and juvenile female coots migrated simultaneously in autumn, but adult females completed migration by 1 November. A few juveniles and adult males migrated in December. Adult coots preceded yearlings in spring. Despite annual and between-lake differences in chronology of autumn migration, most coots migrated before waterfowl hunting seasons in Oklahoma. Coot hunting seasons in mid-latitude states should commence before the general waterfowl season where management goals are to increase hunter interest and the harvest of birds. J. WILDL. MANAGE. 49(1):241-246 Information on the chronology of movements by migratory game birds is essential to regulating harvest (Crissey 1965). Changes in regulations have provided hunters with greater harvest opportunities for waterfowl species migrating earlier than others (Martinson et al. 1966) or species not as vulnerable to shooting pressure (Crissey 1965). The chronology of migration of American coots has received little attention relative to harvest regulations and migration of different ageand sex classes, presumably because hunters have little interest in harvesting coots (Fredrickson et al. 1977:143, Gorenzel 1979:69). Nevertheless, annual harvest of coots averaged 1.17 million birds for 1964-76 (Martin 1979:33), and biologists believe the harvest can be increased (Fredrickson et al. 1977:138). Specific data on general and age-specific chronology of migration by coots are therefore necessary to determine potential changes in regulations to allow increased harvest of coots, the effects of such changes on different segments of coot populations, and the timing of habitat manipulations to attract migrating coots (Fredrickson and Taylor 1982). We determined chronology by age and sex of coots during autumn and spring migrations in Oklahoma to determine the overlap between coot migration chronology and waterfowl season dates and to elucidate patterns of differential migration by age and sex. We thank S. A. Martin, D. Martin, T. C. Tacha, M. E. Heitmeyer, D. P. Hector, D. Latham, P. Harjo, and others for field and laboratory assistance. Personnel of the Okla. Dep. of Wildl. Conserv. provided valuable logistical assistance. We also thank M. W. Weller, L. H. Fredrickson, W. P. Gorenzel, M. E. Heitmeyer, J. W. Lish, F. Schitoskey, and L. G. Talent for helpful comments on the manuscript. E. Waugh and D. Savage granted permission to use Sooner Lake and Lake Carl Blackwell as study areas, respectively. W. D. Warde provided statistical advice. This study was funded by the Accelerated Res. Program for Migratory Shore and Upland Game Birds, U.S. Fish and Wildl. Serv. Contract #14-16-0009-79-085; Oklahoma State Univ.; and the Oklahoma State Univ. Mus. of Nat. and Cult. Hist. The Okla. Coop. Wildl. Res. Unit is supported by the Okla. Dep. of Wildl. Conserv., Oklahoma State Univ., the U.S. Fish and Wildl. Serv., and The Wildl. Manage. Inst.