Geology topics
R. J. Greenwood
Publications and source records attributed to R. J. Greenwood.
Reproduction and development of four mallard lines
Abstract has not been submitted
Ice on waterfowl markers
Wild and captive giant Canada geese (Branta canadensis maxima) and captive mallards (Anas platyrhynchos) accumulated ice on neck collars and/or nasal saddles during winter storm periods in 1971 and 1972. Weather conditions associated with icing were documented, and characteristics of icing are discussed. Severe marker icing occurred during subfreezing weather when the windchill reached approximately -37 deg.C. Birds appeared able to de-ice nasal saddles in most instances.
Influence of radio packs on captive mallards and blue-winged teal
Back-mounted radio packs of three weights were attached to 30 captive mallards (Anas platyrhynchos) and 30 blue-winged teal (A. discors), and physical condition of the birds was evaluated for 12 weeks. All groups with radio packs lost more weight than did control groups. Feather wear often followed by skin irritation occurred in the axillary region of the wings on 90 percent of the treated birds within 1 week, and on the backs of 55 percent of the treated birds within 4 weeks after the radio packs were attached. The treated birds appeared preoccupied with the radio packs and exhibited a partial aversion to swimming.
Effect of certain anesthetic agents on mallard ducks
Four anesthetic agents used in human or veterinary medicine and 3 experimental anesthetic preparations were evaluated for effectiveness in inducing narcosis when administered orally to game-farm mallard ducks (Anas platyrhynchos).Tribromoethanol was the only compound to satisfy criteria of initial tests. Mean duration of the induction, immobilization, and recovery periods was 2.4 minutes, 8.7 minutes, and 1.3 hours, respectively, at the median effective dosage for immobilization (ED50; 100 mg./kg. of body weight). The median lethal dosage (LD50) was 400 mg./kg. of body weight.Tribromoethanol was also tested on mallards during the reproductive season. Effects on the hatchability of eggs or the survival of young were not detected.
Alula removal technique for identifying wings of released waterfowl
A technique for marking waterfowl ducklings less than 1 day old was developed to permit subsequent identification in the hand. Marking was accomplished by removing the alulae from wings of mallard ( Anas platyrhynchos ) ducklings with a small scissors or clipper. No differences in growth rate, behavior, or flight capability were noted between clipped and nonclipped birds. Thirty-five hundred ducklings were clipped when less than 1 day old, and 1,880 of these birds were subsequently examined at 4 1/2 weeks of age. Significant ( P <0.01) differences in successful removal of right and left alulae indicate that right-handed persons should exercise more care when clipping left wings than when clipping right wings. Alula removal appears to be effective for marking the wings of waterfowl.
Mallard hatching from an egg cracked by freezing
The eggs of early-nesting waterfowl in North Dakota are frequently exposed to subfreezing temperatures. Mallards ( Anas platyrhynchos ) and Pintail ( Anas acuta ), normally the first ducks to arrive in the spring, begin limited early nesting in min-April. Nighttime temperatures during this period frequently drop below freezing, and late spring blizzards are not unusual.