Reproductive Success and Nest-Site Selection in a Cooperative Breeder: Effect of Experience and a Direct Benefit of Helping

Abstract

We determined whether nest-site characteristics influence reproductive success and whether experience influences nest-site selection in a population of cooperatively breeding Long-tailed Tits (Aegithalos caudatus). Nest predation was high; only 17% of breeding attempts resulted in fledged young. The height of nests was an important determinant of success; low nests were significantly more successful than high nests. A breeder's age, natal nest site, and breeding experience had no significant effect on nest-site selection. However, failed breeders who helped at the successful nests of conspecifics built subsequent nests lower than nests built prior to their helping experience. Failed breeders who did not help showed no reduction in tlse height of subsequent nests. Moreover, the subsequent reproductive success of failed breeders who helped was significantly higher than that of failed breeders who did not help. We conclude that helpers gain information on nest-site quality through their helping experience and thus gain a direct fitness benefit from their cooperative behavior. We suggest that experience as a helper offers a more reliable cue to nest-site quality than breeding experience because helpers are associated with nests only during the nestling phase when few nests are depredated. In contrast, although successful breeders may experience success with a low nest, they are even more likely to have experienced the failure of low nests because of the high rate of nest predation.A MAJOR DETERMINANT of reproductive success for many organisms is the ability of breeders to protect their offspring from predation. This is particularly true of many open-nesting passerines where the rate of nest predation may be extremely high (Lack 1954, Ricklefs 1969, Martin 1995). A variety of antipredator strategies has evolved among birds to reduce nest predation, including colonial or dispersed breeding, use of cavities, nest concealment or camouflage, elaborate nest design, and protective nesting associations (see Collias and Collias 1984). Numerous studies have shown an intraspecific relationship between nesting success and various characteristics of nests or nest sites, e.g. nest structure (Baeyens 1981), nest density (Andersson and Wiklund 1978, Potts et al. 1980, Hatchwell 1991, Chamberlain et al. 1995, Meilvang et al. 1997), and nest conspicuousness (Picman et al. 1993, Hatchwell et al. such effect (e.g. Holway 1991, Colwell 1992, Filliater et al. 1994, Cresswell 1997a). If predation risk is random with respect to nest-site char-E-mail: b.hatchwell@sheffield.ac.uk acteristics, then no consistent selection may exist for choice of particular nest sites. However, if breeding success is consistently related to certain nest traits, then high rates of nest predation will exert strong directional selection against the choice of low-quality sites by breeders, resulting in low variance in the critical characteristics. Alternatively, in the absence of consistent selection for particular nest sites, site choice may be a variable trait, w...

Divorce in cooperatively breeding long–tailed tits: a consequence of inbreeding avoidance?

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Adaptive Advantages of Cooperative Courtship for Subordinate Male Lance‐Tailed Manakins

“…Alternatively, there are three mechanisms by which beta males may obtain benefits from associating with alphas in the absence of a strict queuing system. First, cooperation may provide opportunities to assess territory quality (Boulinier et al 1996;Hatchwell et al 1999). However, adult males that do not display for females are frequently observed at display areas (e.g., 38.3% ± 15.4% of observation sessions in 2002, « = 22 display areas) and are tolerated by the alpha and beta males, suggesting that cooperation in displays is not necessary to gather information about territory quality.…”

Analysis of Ring Recoveries of European Turtle DovesStreptopelia turtur— Flyways, Migration Timing and Origin Areas of Hunted Birds

“…Nest sites provide the basic needs of breeding adults, eggs and young, including protection from inclement weather (Sadoti, 2008) human disturbance Hanane & Besnard, 2014) and predators (Hatchwell et al, 1999) and offering proximity to food sources (Wiehn & Korpimaki, 1997). Identifying the ecological factors associated with nest site selection in both natural and artificial habitats and at diverse spatial scales: including nest-tree, nest-site, territory and landscape, is therefore important for determining high-priority protected areas.…”