Pen-Reared Fulvous Tree Ducks Used in Movement Studies of Wild Populations

Abstract

To obtain movement data on wild fulvous tree ducks (Dendrocygna bicolor) 165 immature pen-reared fulvous tree ducks were color-marked and released in three southeast Texas counties in JulyOctober 1969/70. Nine (5 percent) of the marked birds were recovered from 3 days to 9 months after release, and an additional 15 birds provided sight records. Many released birds apparently became integrated into the wild populaffon, all of those observed were with wild flocks. Six birds were recovered over 50 miles from the release sites. Four released in late July to mid-September had moved eastward and two went southward in September or later. Five were still in the Texas-Louisiana rice belt ( three in late November). The sixth bird was recovered in October in Veracruz, which supports the assumption that U.S. Gulf Coast nesting populations winter in southern Mexico. J. WILDL. MANAGE. 37(2): Z 7 -Z 7S Fulvous tree duck numbers have drastically declined in the rice belt of southeast Texas since 1960, apparently as a result of mortality from exposure to rice pesticides ( Flickinger and King 1972 ) . Each year from April through June 1967 through 1969, we recorded less than 1,000 wild adults in the 14 counties that provide the major fulvous tree duck habitat. Baird ( 1963 ) suggested that fulvous tree duck movements could be reIated to a stress condition from insecticide applications. In 1969 and 1970 we color-marked, banded, and released young pen-reared fulvous tree ducks at three locations in the Texas rice belt. This was done in the hope that they would join vild flocks to determine areas other than the nesting locality svhere the birds might be exposed to agricultural pesticides. Little is known of the local and seasonal movements of nesting populations of fulvous tree ducks in rice-growing areas of Texas and Louisiana. Singleton ( 1953:26 ) reported that summer residents in Texas migrated south into SIexico prior to the fall hunting season. Texas breeders migrate south along the coast mostly in September and return in April ( Leopold 1959:158 ) . McCartney (1963:38) reported that any tree ducks in Louisiana before 1 April should be considered a vanguard. It is generally assumed that most of the Louisiana populations migrate southward along the Texas Gulf Coast ( Lynch 1943, Meanley 1 56, McCartney 1963) and winter in Mexico (Meanley and Meanley l9S9; McCartney 1963:116). However, there are no banding records to support this view (Meanley and Meanley 1959) . A. B. S. Cuevas, Mexican biologist ( Personal communication ), reported that fulvous tree ducks, presumably from the United States, migrate southsvard in Mexico beginning in early October. Up to 88 percent of these winter in southern Veracruz, Tabasco and coastal areas of Guerrero, Oaxaca, and Chiapas, but the population appears to be declining there also. Although the species was not abundant, Leopold ( 1959 ) found the largest winter numbers in Mexico in coastal Guerrero. The Bureau of Sport Fisheries and Wildlife Winter Waterfowl Survey showed 713 fulvous tree ducks on the Gulf Coast of Mexico in January 1963. The largest number (530) were in Veracruz (A. R. Brazda, personal communication). Some recent banding of wild fulvous tree ducks conducted on the U.S. Gulf Coast inJ. Wildl. SIanage. 37(2):1973 171 This content downloaded from 157.55.39.70 on Tue, 06 Sep 2016 05:28:41 UTC All use subject to http://about.jstor.org/terms 172 MOVEMENT OF FULVOUS TREE DUCKS * FllPkinger et al. Iberia Parish; these birds had been banded at this same site. Three were recaptured in December: one the year *at it was banded (1937), one a year after it was banded (1942), and one, two years after it was banded (1942). The remaining bird was recaptured during the 194445 hunting season (three years after it was banded) . One other recovery of a banded fulvous tree duck in Texas was a wild male banded at the Salton Sea in southern California in March l9S6 and recovered in November 1957 near Fulshear, Fort Bend County, in the southeast Texas rice belt. For aiding in our study we thank R. NV. Clapper, Refuge Manager, Anahuac National Wildlife Refuge, and rice growers A. A. Priesmeyer of E1 Campo and H. E. Rawlings of Iowa Colony, Brazoria County.