The roles of social information, asocial information, and initial bias in nest-building decisions.

Animals can use asocial (e.g., environmental cues) or social (e.g., conspecific behavior) information when making decisions. We investigated decisions made by zebra finches when asocial and social sources conveyed agreeing or conflicting information, and assessed the influence of initial bias on decision making. Finches completed an initial preference test ranking preference for three colors of nest-building material. Birds in the agree group (n = 14) then observed demonstrators build nests using nonpreferred color material (social information) that matched the environment color (asocial information). Birds in the conflict group (n = 15) observed demonstrators build nests with nonpreferred color material that did not match the cage environment (another nonpreferred color). A final preference test assessed any changes in color preference. The agree group reduced average preference for their initially preferred color, but did not significantly increase average preference for the asocial/social colors. The conflict group also reduced average preference for the initially preferred color and also increased preference for the socially demonstrated color. Observers with stronger initial bias were less likely to choose the socially demonstrated color than observers with weaker initial bias. This shows that social information informs nest-building decisions, even when in conflict with asocial information. However, bias influences social information use and adds nuance to how different individuals use information when making decisions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Zebra finches have style: Nest morphology is repeatable and associated with experience.

We investigated whether birds build nests in repeatable styles and, if so, whether styles were associated with past nest-building experience. Laboratory, captive bred zebra finches in an Experimental group were given nest-building experience, whereas, birds in a Control group were not. Each pair (n = 20) then built four nests that underwent image analyses for nest size, geometric shape and entrance orientation. Birds built nests in repeatable styles, with lower morphometric variation among nests built by the same pair and higher morphometric variation among nests built by different pairs. Morphology was not associated with construction time, body weight, nor age of birds. We found lower morphometric variation among nests built by the Experimental group, which also used less material to build nests compared to the Control group. Prior experience may therefore have been advantageous, as learning to reduce material usage while achieving a similar product (nest) may have lowered building costs.

Genetic divergence and evidence of human-mediated translocation of two-fingered sloths (Choloepus hoffmanni) in Costa Rica.

Sloths are notoriously slow and consequently have limited dispersal ability, which makes them particularly vulnerable to the effects of habitat fragmentation and degradation. Sloths in Costa Rica are considered of conservation concern due to habitat loss, livestock production and increasing urbanization. Reintroductions from rescue centres are commonplace across the country, yet their genetic diversity and population structure are unknown, and there is currently little consideration of the genetic background prior to intervention or releases. We used microsatellite analysis to undertake the first exploratory investigation into sloth population genetics in Costa Rica. Using data from 98 two-fingered sloths (Choloepus hoffmanni) from four different geographic regions, we determined the presence of four potential genetic groups, three of them with minimal population structuring despite the limited dispersal ability and presence of physical barriers. Sloths from the North appear to represent a highly distinct population that we propose may require management as a discrete unit for conservation. We stress the need for additional analyses to better understand the genetic structure and diversity of North andWest regions and suggest that rescue facilities in Costa Rica should consider the genetic background of rehabilitated sloths when planning future reintroductions. Our results also highlight the threat posed by physical isolation due to widespread urbanization and agriculture expansion for a species with a weak dispersal ability.