Survival, movement, and habitat selection of male Rio Grande wild turkeys in the Texas Panhandle and southwestern Kansas

Date

2003-08

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Publisher

Texas Tech University

Abstract

Wildlife managers depend on accurate information regarding wild turkey survival patterns and survival rates to properly manage turkey populations. Male Rio Grande wild turkeys (Meleagris gallopavo intermedia) have not previously been studied in the Texas Panhandle and southwestern Kansas. Furthermore, the effect of movements on turkey survival has not been studied. From January 2000 through August 2002, we studied survival and movement of 107 juvenile male and 115 adult male radio-marked Rio Grande wild turkeys on 4 study sites in the Texas Panhandle and southwestern Kansas. We hypothesized that male Rio Grande wild turkey survival differed among study sites, seasons, and age classes and that survival rates were inversely correlated with movement rates. Based on previous studies, we predicted that males would experience lowest survival during spring and that there would be no difference in survival between age classes. We also predicted that higher movement rates would lead to lower survival rates. Hunting accounted for ordy 18.5% of all mortalities and was censored in order to investigate natural mortality patterns. Juvenile males had higher annual survival rates than adults (0.597 versus 0.364). Juvenile male survival did not differ among seasons. Adult male turkey survival was higher during summer (0.915) than during spring (0.725), autumn (0.671), and winter (0.851). During seasons that involved long-distance, range shifting movements, males had lower survival rates than during seasons when within range movements were common. Turkeys that shifted ranges had lower survival rates than turkeys that remained within 1 core-use area. Also, survival rates increased as time since range shift increased. Most mortality was attributed to predation by coyotes {Canis latrans). However, evidence of mortality due to disease, emaciation, and other forms of predation, such as bobcats {Lynx rufus), were likely masked by coyote sign associated with scavenging. Managers should be aware of the presence of natural mortality factors that are evident in lightly-hunted populations. Managers interested in increasing the survival of male Rio Grande wild turkeys should concentrate on efforts that will provide needed resources in close proximity to roosts.

Habitat use has not been described for male Rio Grande wild turkeys in the northern extent of their natural range. We described the characteristics of roost trees and compared the characteristics of diurnal habitat used for different behaviors (displaying, loafing, and feeding) by male Rio Grande wild turkeys in the Texas Panhandle and southwestern Kansas. Most turkeys roosted in eastern cottonwoods (Populus deltoides), but black locusts (Robinia pseudoacacia) and net leaf hackberries {Celtis reticulata), were also frequently used. Mean roost tree dbh, height, and height of lowest branch was 49.9 cm, 13.6 m, and 3.4 m, respectively. Important characteristics of displaying habitat included low visual obstruction and low shrub density. Loafing habitat was characterized by greater canopy cover and densities of trees and large shrubs than random sites. Spring feeding habitat had lower visual obstruction than summer feeding habitat, with spring feeding areas similar to displaying areas and summer feeding areas similar to loafing areas. This suggested that turkeys seemed to feed opportunistically in areas chosen for other purposes. Habitat management for male Rio Grande wild turkeys should focus on protecting remaining riparian roost areas and encouraging cottonwood regeneration. Openings for displaying and brushy areas for loafing should be created or maintained in close proximity to traditional roosts.

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