Can chemical cues from a predator change the nest-selection of birds?

The nest-selection process of many birds can be affected by traces of potential predators. However, it remains debatable if birds are capable of recognizing and responding to chemical cues of predators when selecting their nest sites. To investigate this, I installed a pair of nest boxes at 12 sites in 2013 and 2014 and 24 sites in 2015 and 2016, each with nest conditions that differed for two variables, that is, height (high or low), hole depth (deep or shallow). Under these experimental conditions, tree swallows displayed a strong preference for high nests over low ones and deep hole nests over shallow holes. In a consecutive experiment, we applied chemical cues (i.e. urine, feces) of domestic cats to the preferred nests to determine if this would alter the nests selected; the chemical cues led to a stepwise alteration in the nests selected. The birds changed their nest selection by chemical cues of a predator when one variable (nest height or hole depth) was applied. Interestingly, however, when provided with a choice between the most preferred nest combination (high and with a deep hole) and the least preferred nest combination (low and with a shallow hole), tree swallows selected the most preferred nest even in the presence of the chemical cues.

Pemetaan Spesies Kelelawar Berdasarkan Pola Pemilihan Sarang di Gua Gale-gale Bangkang dan Gua Raksasa Tanjung Ringgit

This study aims to determine the pattern of nest selection in bat species inhabiting the Bangkang Gale-gale Cave in Prabu Village, Pujut District, Central Lombok Regency, and Tanjung Ringgit Giant Cave in Sekaroh Village, Jerowaru District, East Lombok Regency. Nests are an important component of bat life. Most types of bats live in colonies in nesting and foraging for food. This research method is descriptive exploratory by mapping cave zones, making squares, analyzing the richness and abundance of bat species at each bat nesting site. The results showed that the nest selection pattern in Gale-gale Cave, namely: Rhinolopus acuminatus, Rhinopoma microphylum, and Rhinolopus simplex were in the same group in zone / zone I. Whereas Chaerephon plicata could be found inhabiting zone / zone II, and Hipposideros ater. saevus inhabit zone / zone III. The pattern of nest selection in the Giant Cave Tanjung Ringgit, Macroglossus minimus and Eonycteris spelaea was found in both zone zone II and zone III caves. Hipposideros ater saevus and Hipposideros diadema are in the same group, namely on the border between zone II and zone III, namely the left and right sides of zone III, or not far from the water source in the cave ± 2 m above the water source, and Rosettusa amplxicaudatus inhabit zone / zone III Giant Cave Tanjung Ringgit.

Underlying mechanisms and ecological consequences of variation in exploratory behavior of the Argentine ant, Linepithema humile

Uncovering how and why animals explore their environment is fundamental for understanding population dynamics, the spread of invasive species, species interactions etc. In social animals, individuals within a group can vary in their exploratory behavior and the behavioral composition of the group can determine its collective success. Workers of the invasive Argentine ant (Linepithema humile) exhibit individual variation in exploratory behavior, which affects the colony’s collective nest selection behavior. Here we examine the mechanisms underlying this behavioral variation in exploratory behavior and determine its implications for the ecology of this species. We first establish that individual variation in exploratory behavior is repeatable and consistent across situations. We then show a relationship between exploratory behavior and the expression of genes that have been previously linked with other behaviors in social insects. Specifically, we find a negative relationship between exploratory behavior and the expression of the FOR gene. Finally, we determine how colonies allocate exploratory individuals in natural conditions. We find that ants from inside the nest are the least exploratory individuals, while workers on newly formed foraging trails are the most exploratory individuals. Furthermore, workers in the spring, when new resources emerge, are more exploratory than workers in the winter, potentially allowing the colony to find and exploit new resources. These findings reveal the importance of individual variation in behavior for the ecology of social animals and provide mechanistic and functional explanations for how such behavioral variation can emerge.

Nest prospecting brown-headed cowbirds ‘parasitize’ social information when the value of personal information is lacking

Brood parasites face considerable cognitive challenges in locating and selecting host nests for their young. Here, we test whether female brown-headed cowbirds, Molothrus ater , could use information acquired from observing the nest prospecting patterns of conspecifics to influence their own patterns of nest selection. In laboratory-based experiments, we created a disparity in the amount of personal information females had about the quality of nests. Females with less personal information about the quality of two nests spent more time investigating the nest that more knowledgeable females investigated. Furthermore, there was a strong negative relationship between individual's ability to track nest quality using personal information and their tendency to copy others. These two contrasting strategies for selecting nests are equally effective, but lead to different patterns of parasitism.

The importance of scale-dependent ravine characteristics on breeding-site selection by the Burrowing Parrot, Cyanoliseus patagonus

In birds, the environmental variables and intrinsic characteristics of the nest have important fitness consequences through its influence on the selection of nesting sites. However, the extent to which these variables interact with variables that operate at the landscape scale, and whether there is a hierarchy among the different scales that influences nest-site selection, is unknown. This interaction could be crucial in burrowing birds, which depend heavily on the availability of suitable nesting locations. One representative of this group is the burrowing parrot, Cyanoliseus patagonus that breeds on specific ravines and forms large breeding colonies. At a particular site, breeding aggregations require the concentration of adequate environmental elements for cavity nesting, which are provided by within ravine characteristics. Therefore, intrinsic ravine characteristics should be more important in determining nest site selection compared to landscape level characteristics. Here, we assess this hypothesis by comparing the importance of ravine characteristics operating at different scales on nest-site selection and their interrelation with reproductive success. We quantified 12 characteristics of 105 ravines in their reproductive habitat. For each ravine we quantified morphological variables, distance to resources and disturbance as well as nest number and egg production in order to compare selected and non-selected ravines and determine the interrelationship among variables in explaining ravine differences. In addition, the number of nests and egg production for each reproductive ravine was related to ravine characteristics to assess their relation to reproductive success. We found significant differences between non-reproductive and reproductive ravines in both intrinsic and extrinsic characteristics. The multidimensional environmental gradient of variation between ravines, however, shows that differences are mainly related to intrinsic morphological characteristics followed by extrinsic variables associated to human disturbance. Likewise, within reproductive ravines, intrinsic characteristics are more strongly related to the number of nests. The probability of producing eggs, however, was related only to distance to roads and human settlements. Patterns suggest that C. patagonus mainly selects nesting sites based on intrinsic morphological characteristics of ravines. Scale differences in the importance of ravine characteristics could be a consequence of the particular orography of the breeding habitat. The arrangement of resources is associated to the location of the gullies rather than to individual ravines, determining the spatial availability and disposition of resources and disturbances. Thus, nest selection is influenced by intrinsic characteristics that maximize the fitness of individuals. Scaling in nest-selection is discussed under an optimality approach that partitions patch selection based on foraging theory.

Computational model of collective nest selection by ants with heterogeneous acceptance thresholds

Collective decision-making is a characteristic of societies ranging from ants to humans. The ant Temnothorax albipennis is known to use quorum sensing to collectively decide on a new home; emigration to a new nest site occurs when the number of ants favouring the new site becomes quorate. There are several possible mechanisms by which ant colonies can select the best nest site among alternatives based on a quorum mechanism. In this study, we use computational models to examine the implications of heterogeneous acceptance thresholds across individual ants in collective nest choice behaviour. We take a minimalist approach to develop a differential equation model and a corresponding non-spatial agent-based model. We show, consistent with existing empirical evidence, that heterogeneity in acceptance thresholds is a viable mechanism for efficient nest choice behaviour. In particular, we show that the proposed models show speed–accuracy trade-offs and speed–cohesion trade-offs when we vary the number of scouts or the quorum threshold.