H. Randolph Perry, Jr.

The breeding chronology of the mottled duck (Anasfulvi[(ula maculosa) was investigated during a 2-year study in southwest Louisiana. Gonadal measurements were recorded from 37 hunter-killed and 158 collected mottled ducks. A correlation analysis revealed that the ratios of combined testis length to body weight and oviduct width to body weight most accurately revealed reproductive status for males and females, respectively. A quadratic model produced the most significant regression of reproductive status on time for both sexes in 1978 and 1979. Mottled ducks remained sexually quiescent...

Errors generated when determining the sex of mourning doves (Zenaida macroura) from plumage characteristics and their effect on sex ratio projections from banded and shot samples were evaluated in a 2-year study in Louisiana. Error rates (percentage misclassified) of 3.8% and 5.0% were obtained from a sample of 236 banded and 1,820 hunter-killed doves, respectively. Converting data to sex ratios produced actual error rates of 13. I% for the banded sample and 1.1% for doves killed by hunters. No significant differences were detected in ability to determine sex in doves from plumage...

A total of 112 standardized counts of roosting ducks were made at 4 roosts within 2 typical northeastern North Carolina swamps from Sepember-March, 1972-73 and 1973-74. Zero to 60 ducks were observed per count with an overall average of 7.5. Approximately 97% of all ducks observed were wood ducks (Aix sponsa). No differences in numbers of roosting ducks were detected between years or swamps in spite of major watershed differences. However roost site differences within a swamp and several year interactions were important. A significant cubic relationship over time was noted in the average...

Several collar materials (nylon webbing, nylon-covered rubber tubing, nylon webbing lined with nutria fur, boltaron hard plastic, latex tubing, and a nylon harness) and 2 transmitter weights (60 and 120 g) were comparatively tested for potential use as radio transmitter units for nutria (Myocastor coypus). Most collar materials caused dermatitis, abrasions, or lesion around the neck and the animals continuously worked their way out of the nylon harness. The only combination which did not cause any adverse physiological reaction was the nylon-covered rubber tubing collar with a 60 g dummy...

Three hundred and two snipe were collected in an effort to evaluate proposed aging and sexing techniques and to determine a practical method of aging and sexing the common snipe by external characters. Thirty-one external variables were selected for measurement based on their potential to discriminate between ages or sexes of various birds as shown by past studies. The minimum percent misclassification of sexes (28.38%) and ages (22.64%) was obtained when the top 25 sex~ ing and top 22 aging variables were formulated into a discriminant function (Z), constructed so as to minimize the...