Test of the Ecological Basis of Cooperative Breeding in Red-Cockaded Woodpeckers

Predation risk is an ecological constraint for helper dispersal in a cooperatively breeding cichlid

“…First, the experimental removal of breeders resulted in helpers inheriting the breeding position (Brown & Brown 1981;Hannon et al 1985;Komdeur 1992;Walters et al 1992;Komdeur et al 1995;Balshine-Earn et al 1998;Field et al 1998;Shreeves & Field 2002) or nearby helpers dispersing and filling the vacancy (Pruett-Jones & Lewis 1990). These observations show that helpers are capable of independent breeding when given the opportunity, but are prevented from doing so by aggressive exclusion of competitors.…”

“…Although ecological constraints have often been assumed to be an important factor in forcing helpers to stay at home, experimental evidence is scarce. Experiments have been confined to manipulating the availability of (high quality) breeding opportunities in the neighbourhood of helpers, and subsequently measuring helper dispersal and independent breeding (Pruett-Jones & Lewis 1990;Ligon et al 1991;Du Plessis 1992;Komdeur 1992;Walters et al 1992;Komdeur et al 1995;Field et al 1998). So far, no study has manipulated other environmental/ecological factors, for example predation risk, that may influence the occurrence and extent of cooperative breeding and whether helpers stay at home rather than disperse.…”

Territoriality, Prospecting, and Dispersal in Cooperatively Breeding Micronesian Kingfishers (Todiramphus Cinnamominus Reichenbachii)

“…Resource availability has been shown to cause sociality in Seychelles Warblers (Acrocephalus sechellensis; Komdeur 1991Komdeur , 1992Komdeur , 1994 and Red-cockaded Woodpeckers (Picoides borealis; Walters et al 1992), and larger territories and greater resources have been correlated with sociality in other cooperative species, such as Splendid Fairy-wren (Malurus splendens; Brooker and Rowley 1995). Greater or higherquality resources on natal areas can also infl uence reproductive success (Forbes et al 2002, 390 [Auk, Vol.…”

“…In many cooperatively breeding species, some individuals disperse as juveniles, whereas others delay for extended periods (Koenig and Pitelka 1981, Brown 1987, Stacey and Koenig 1990, Walters et al 1992, Ligon 1999, Ekman et al 2004. This patt ern implies that each individual gathers information about resource quality, territory occupancy, and breeding vacancies in nearby areas before making dispersal decisions.…”

Diet of Nestling Red-Cockaded Woodpeckers at Three Locations

“…The effects of habitat loss (Conner and O'Halloran 1987, Rudolph and Conner 1991, Walters et al 2002 and fire suppression (Conner andRudolph 1989, Costa andEscano 1989) have been well studied in regard to nesting habitat (i.e. the cavity tree cluster and area within approximately 61 m of the cluster), which has been considered the foremost limiting factor for RCW populations (Walters et al 1992(Walters et al , 2002. As nesting constraints are now mitigated through techniques such as prescribed burning and artificial cavity construction (Copeyon 1990, Allen 1991, foraging habitat (i.e.…”