Great Egret Preference for Catfish Size Classes

Several species of fish-eating birds are commonly observed near aquaculture facilities in the southern United States. An understanding of the relationships between these birds and specific commodities is needed to interpret and manage bird impacts to aquacultural production. We conducted two foraging experiments to evaluate the preference o f Great Egrets (Ardea alba) for three specific size classes of Channel Catfish (Zctalurus punctatus). During six no-choice feeding trials, egrets consumed significantly more small (7.5-10 cm) fingerlings than medium (13- 18 cm) or large (23-23 cm) catfish. Egrets captured 19 large catfish, and ingested only two, even when no other fish were available. During two-choice trials, Great Egrets significantly preferred small fingerlings to medium-sized fish, and medium-sized catfish to large fish. Handling time was directly related to the size of catfish ingested. Handling time was inversely related to the number of catfish ingested from each size class, particularly when Great Egrets were given a choice between two catfish size classes. Thus, we infer that the ease of capture and physical defenses (e.g., catfish spines) associated with particular foods affect Great Egret foraging preferences. Management of Great Egret impacts to aquacultural production should focus on dispersing egrets from ponds containing small (\u3c18 cm) Channel Catfish, rather than generalized dispersal at all ponds on all farms. Received 1 October 2000, accepted 18 April 2001

Green and Blue Lasers are Ineffectivefor Dispersing Deer at Night

Over-abundant populations of white-tailed deer (Odocoileus virginianus) create agriculturaland human health and safety issues. The increased economic damage associated with locally overabundant deer populations accentuates the need for efficient techniques to mitigate the losses. Although red lasers can be an efficient tool for reducing damage caused by birds, they are not effective for deer because deer cannot detect wavelengths in the red portion of the spectrum. No research has been conducted to determine if lasers of lower wavelengths could function as frightening devices for deer. We evaluated agreen laser (534nm, 120mW)and 2 models of blue lasers (473nm, 5 mW and 15 mW) to determine their efficacy in dispersing deer at night. Deer were no more likely to flee during a green or blue laser encounter than during control encounters. The green and blue lasers we tested did not frighten deer

Red lasers are ineffective for dispersing deer at night

Populations of white-tailed deer (Odocoileus virginianus) and the number of deer-human conflicts have increased in recent years, emphasizing the need for efficient and inexpensive methods to reduce site-specific deer damage. Recent research using laser technology to disperse a variety of bird species has yielded promising results, prompting wildlife professionals and the public to question whether lasers could play a role in reducing damage and conflict with mammals, primarily deer. We evaluated 2 red lasers (63-650 nm) to determine their effectiveness as devices to frighten deer. No differences occurred in flight response between lasers or between the control and lasers. We suggest that deer were not frightened by either model of laser because they could not detect red laser beams or their intense brightness. Red lasers do not appear to have potential as frightening devices for deer