Nesting Activities of Northern Mockingbirds in Northern Louisiana

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Data collected from 675 active Northern Mockingbird (Mimus polyglottos) nests in northern Louisiana from 1963-1979 were analyzed. Nesting began in early March and continued through early August. Completed clutches contained 2-6 (x = 3.7?0.05) eggs; broods contained 1-5 (x = 3.2 ? 0.05) nestlings. Eggs usually hatched after 13 days of incubation and nestlings fledged 12 days later. A minimum of 42 plant species was used as nesting sites. Average nest height increased as the season progressed. Variation in the number of young fledged was evaluated. The Mayfield exposure method was used to determine the probability of surviving the nesting period. Abandonment and predation were the major causes of nest losses. We investigated nesting activities and nest site selection of the Northern Mockingbird in the northern upland section of Louisiana. Laskey (1962) in Tennessee, Bent (1964) among many states, Woolfenden and Rohwer (1969) in Florida, and Graber et al. (1970) in Illinois have compiled the most com- plete local records on nesting for this species. Our objectives were to sum- marize reproductive data based on a large number of observations for an important non-game species, especially since no previous major nesting study had been conducted in the southcentral United States. STUDY AREAS AND METHODS.-Observations were made throughout Louisiana north of Alexan- dria. The area, characterized by gently rolling hills, elevations of 15-161 m, is either under agricul- tural development, in predominantly mixed pine-hardwood forest, or urbanized. The majority of nests were found in Lincoln Parish, especially on the campus and farms of Louisiana Tech University (LTU) and amid the yards and woodlots of Ruston. The 92-ha main campus of LTU is located 1-3 km west of downtown Ruston. Numerous large oaks (Quercus spp.) and ornamental shrubs (holly, juniper, camellia, azalia, ligustrum, among others) are abundant