Dietary Conjugated Linoleic Acid to Control the Population of Wild Bird Species Considered a Pest

Abstract

Many bird species conflict with human economic, aesthetic, or vital interests (Wetherbee et al. 1964). Pigeons (Columbia livia) cause tremendous damage and pollution to park benches, statues, vehicles, buildings, and domestic water supplies due to the highly corrosive uric acid contained in their droppings. Previous attempts to manage bird populations have failed because of high cost, variable success, and difficulty in application. A previous study demonstrated that certain dietary fatty acids can cause embryonic mortality in fertile eggs (Donaldson and Fites 1970). This suggests a potential approach for controlling wild bird populations. Cook et al. (1996) reported that dietary conjugated linoleic acid (CLA; a mixture of positional and geometrical isomers of linoleic acid) contributed to the control of bird populations at airports, cattle feed lots, and parks. Foods derived from ruminant animals contain the highest natural concentrations of CLA (Chin et al. 1992). Scientists have attributed multiple beneficial properties to CLA, such as anticarcinogenic (Ha et al. 1990), anti-atherogenic (Nicolosi et al. 1997), fat-reducing effects (Park et al. 1997), and immune-enhancing activity in chickens (Cook et al. 1993). A previous study showed that a low-fat diet supplemented with 0.5% CLA caused 100% embryonic mortality in the fertile chicken eggs (Aydin et al. 2001). Another study showed that a diet containing 3%, 2%, or 1% CLA caused 100% embryonic mortality in fertile Japanese quail (Coturnix coturnix japonica) eggs after 6 days, 10 days, or 12 days of feeding, respectively (Aydin and Cook 2004). Researchers suggested that dietary CLA caused significantly higher embryonic mortality in fertile eggs by changing fatty acid composition of egg yolk (Lee 1996, Aydin et al. 2001). On-site management actions such as barriers, scare tactics, chemical repellents, and habitat modifications to control pigeon populations often correlate with high cost, variable success, and difficulty in application (Smith et al. 1999). We investigated the effect of dietary CLA on hatchability of fertile pigeon eggs to determine the potential for using CLA to control the population of wild bird species that are considered pests. Use of CLA could provide managers with a more cost-effective means of controlling pigeon populations. Study Area