Bonobos, chimpanzees, gorillas, and orang utans use feature and spatial cues in two spatial memory tasks

Animals commonly use feature and spatial strategies when remembering places of interest such as food sources or hiding places. We conducted three experiments with great apes to investigate strategy preferences and factors that may shape them. In the first experiment, we trained 17 apes to remember 12 different food locations on the floor of their sleeping room. The 12 food locations were associated with one feature cue, so that feature and spatial cues were confounded. In a single test session, we brought the cues into conflict and found that apes, irrespective of species, showed a preference for a feature strategy. In the second experiment, we used a similar procedure and trained 25 apes to remember one food location on a platform in front of them. On average, apes preferred to use a feature strategy but some individuals relied on a spatial strategy. In the final experiment, we investigated whether training might influence strategy preferences. We tested 21 apes in the platform set-up and found that apes used both, feature and spatial strategies irrespective of training. We conclude that apes can use feature and spatial strategies to remember the location of hidden food items, but that task demands (e.g. different numbers of search locations) can influence strategy preferences. We found no evidence, however, for the role of training in shaping these preferences

Egg pecking and puncturing behaviors in shiny and screaming cowbirds: effects of eggshell strength and degree of clutch completion

Abstract: Shiny cowbirds (Molothrus bonariensis) are generalist brood parasites that use hosts varying in body and egg size. On the contrary, screaming cowbirds (M. rufoaxillaris), which are larger than shiny cowbirds, are host specialist that use mainly one host of similar body and egg size. Both parasites peck and puncture eggs when visiting nests. Through puncturing eggs, cowbirds can reduce the competition for food their chicks face (reduction of competition hypothesis), but the same behavior could also be a mechanism to enforce host to renest when nests are found late in the nesting cycle (farming hypothesis). Eggshell strength increases the difficulty to puncture eggs and therefore may modulate egg-pecking behavior. To test these hypotheses, we studied the effect of the degree of clutch completion and egg size on egg-puncturing behavior. Moreover, we evaluated if morphological differences between cowbird species and eggshell strength affected egg-pecking behavior. We presented captive females a nest with complete (four eggs) or incomplete (one egg) clutches of house wren (small egg size, low eggshell strength), chalk-browed mockingbird (large egg size, intermediate eggshell strength), or shiny cowbird (medium egg size, high eggshell strength). The proportion of nests with punctured eggs was similar for complete and incomplete clutches. Cowbirds punctured more eggs in complete than in incomplete clutches, but in complete clutches, they did not destroy the entire clutch. There were no differences in the egg-pecking behavior between cowbird species, which pecked more frequently the eggs with the strongest eggshell. Our findings are consistent with the reduction of competition hypothesis. Significance statement: Brood parasitic birds do not build nests and raise their chicks. Instead, they lay eggs in nests of other species (hosts), which carry out all parental care. Some brood parasites, like the cowbirds, peck and puncture eggs when they visit host nests. This behavior may help to reduce the competition for food that their chicks face in the nest (reduction of competition hypothesis) or may enforce hosts to renest (farming hypothesis). We experimentally studied egg-pecking and egg-puncturing behaviors in the host generalist shiny cowbird and the host specialist screaming cowbird. We found that the degree of clutch completion and egg size modulate egg-puncturing behavior and eggshell strength modulates egg-pecking behavior. Our results indicate that by puncturing eggs, cowbirds reduce nest competition.Fil: Cossa, Natalia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Tuero, Diego Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Reboreda, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Fiorini, Vanina Dafne. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentin

Parasitic Behaviour of Interspecific Brood Parasitic Females

Interspecific avian brood parasites have to solve unique problems associated with their reproductive habit: they need to recognize potential hosts, search for and locate their nests, monitor nests progress and return to them at the appropriate time for egg-laying. In addition, parasitic females may improve the survival of their own eggs and chicks by removing or destroying part of the clutch content. Lastly, they should avoid egg-laying in nests parasitized by other females and remember the nests in which they have laid eggs to avoid laying two or more eggs in the same host nest to prevent harming their own previously laid eggs and generating competition between their own offspring. In this chapter we summarize information on the behaviour of parasitic females from the moment they start searching for host nests until they parasitize them (Fig. 1). We review the different hypotheses for explaining the recognition of hosts and the cues used to search for and locate their nests. We also review the different adaptive explanations for the removal or destruction of eggs as well as the information on competition among females for host nests and repeat parasitism.Fil: Reboreda, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Fiorini, Vanina Dafne. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Cecilia de Mársico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Gloag, Ros. University of Sydney; AustraliaFil: Scardamaglia, Romina Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentin