Group Territoriality, Dispersal and Population Persistence in an Endangered Species Endangerment Loss of Required/Preferred Habitat Habitat Fragmentation Habitat Degradation Number of Territories Dispersal Distance Between Territories

Red-Cockaded Woodpecker Picoides borealis Endangered USFWS Group Territoriality Cooperative Breeding Male Helpers

Red-Cockaded Woodpecker Excavate Nesting Cavity 80+ Year-Old Pine, Heartwood Endemic Mature Pine Forests, Southeast

Extinction: Causes 1.Demographic Stochasticity Among-Individual Variation 2. Environmental Stochasticity Among-Generation Variation 3. Catastrophe 4. Inadequate Genetic Variation

Avoid Extinction: Viable Population Commonly Large Enough to Withstand Demographic and Environmental Stochasticity Catastrophe Difficult to Plan Red-cockaded Woodpecker USFWS: Large Enough to Avoid Loss Alleles Thru Genetic Drift

Red-Cockaded Woodpecker Recovery Plan Preserve Breeding Habitat and Establish New Populations Maintain Viable Local Populations Challenges Habitat Loss (Fewer Territories) Fragmentation (Greater Dispersal Distance)

Red-Cockaded Woodpecker Letcher, Priddy, Walters & Crowder (1998) Biol. Conservation 86:1 – 14. Between-Sex Behavioral Differences in Dispersal Territory Availability Spatial Aggregation of Territories “Clumped”  Reduced Dispersal Distance

Letcher, Priddy, Walters & Crowder (1998) Biol. Conservation 86:1 – 14. Territories “fixed” by availability of old trees Breeding pair and non-breeding helpers Competition for breeding status/territory Female fledglings disperse, long distance Male fledglings remain as helpers Breed on natal territory Disperse, short distance

Female Life History: Disperse to Breed

Male Life History: Most help before breeding

Letcher, Priddy, Walters & Crowder (1998) Biol. Conservation 86:1 – 14. J. Walters: 25 yrs.; behavior and life histories > 200 groups in North Carolina > 2000 individuals Data to parameterize demography/conservation model Territory number (habitat loss) Spatial pattern (dispersal distances)

Letcher, Priddy, Walters & Crowder (1998) Biol. Conservation 86:1 – 14.

Population Persistence Clutch size (obvious) Female Dispersal (Long Distance) Avoid Mortality, Find Breeding Opportunity Number of Territories Male Dispersal (Short Distance) Find/Compete Breeding Opportunity Spatial Aggregation of Territories