Abstract: Common cuckoos (Cuculus canorus) are obligate brood parasites, laying eggs into nests of small songbirds. The cuckoo hatchling evicts all eggs and young from a nest, eliminating hosts' breeding success. Despite the consistently high costs of parasitism by common cuckoos, great reed warbler (Acrocephalus arundinaceus) hosts sometime accept and other times reject parasitic eggs. To explore the cognitive basis of this seemingly maladaptive variation in host responses, we documented differences in egg rejection rates within 1-day periods just before and during the egg-laying cycle across host nests. Hosts rejected cuckoo eggs at 28% of nests during the pre-egg-laying stage, but when cuckoos exchanged the first host egg with the parasite egg, rejections increased to 75%. Even later, when several host eggs remained in a nest after parasitism, rejection rate fell to 37.5%. Experimental parasitism with conspecific eggs on the first and second day of host laying showed a similar directional change in relative rejection rates, dropping from 35 to 0%. Mistakes in egg discrimination (ejection error and ejection cost) were observed mostly in the latter part of the laying cycle, mainly when nests contained 5-6 eggs. These correlational and experimental patterns of egg rejection support a cognitive process of egg discrimination through several shifts in hosts' optimal acceptance thresholds of foreign eggs. The results are also consistent with the evolution of foreign egg rejection in the context of nest-sanitation (i.e. the removal of foreign objects). Our results suggest that common cuckoo hosts may recognize more eggs than they reject. This implies that the experience of the host with one or more of its own eggs in the clutch is a key factor in rejecting parasite eggs by allowing inspection and learning about their own clutch.

Abstract: Abstract  Relational learning, as opposed to perceptual learning, is based on the abstract properties of the stimuli. Although at present there is no doubt that pigeons are capable of relational behavior, this study aims to further disclose the conditions under which it occurs. Pigeons were trained in an outdoor cage on a matching-to-sample or an oddity-from-sample task, with colored cardboard stimuli presented horizontally. The apparatus involved three sliding lids on which the stimuli were drawn and which, when displaced, revealed the reinforcement. The lids were either adjacent to each other or somewhat separated. Training sessions involved two colors, and test sessions six different colors (same dimension test), or six different shapes (different dimension test). One group of birds trained under the “adjacent” condition failed when tested with new stimuli, but succeeded in both dimension tests after training under the “separate” condition. Two other groups of birds succeeded in all tests after training under the latter condition. These results show that depending on procedural details, pigeons are or are not able to transfer from one visual dimension to another, thus extending previous related findings.

Abstract: Specific genotypes of the rhesus monkey and human serotonin transporter gene (SERT) promoter region are associated with personality traits and serotonergic activity. However, the most commonly studied promoter polymorphism (5-HTTLPR) is monomorphic in many other monkey species. To date, no systematic search for alternative potentially functional polymorphisms across the remaining coding parts of the gene has been undertaken in other primate species, despite the crucial role SERT plays in modulating serotonergic tone. We investigated whether sequence variation in this gene is associated with social rank and serotonin metabolite (5-HIAA) differences in 524 cynomolgus macaques. Sequence variation and extent of linkage disequilibrium (LD) across the regulatory and coding regions were initially characterized in 92 macaques. The exons and promoter contained 28 polymorphisms, more than double that recorded for human SERT. In further contrast to humans, the macaque SERT showed no significant LD. Potentially functional polymorphisms were genotyped in all animals. No individual variants or haplotypes were significantly associated with social rank or 5-HIAA concentrations; however, certain serotonin transporter diplotypes may modulate acquisition of dominance status.

Abstract: The Przewalski`s horse (Equus f. przewalskii) was extinct in the wild by the mid-sixties of the past century. The species only survived due to captive breeding from 13 founder individuals. In 1992 a reintroduction program was initiated in the Great Gobi B Strictly Protected Area in southwestern Mongolia. During it“s initial years, the project concentrated exclusively on P-horses. In the past decade activities have expanded significantly. The ecological project start point can be summed up as follows: i) species is extinct in the wild, ii) severe bottleneck, iii) practically no ecological data prior to extinction, iv) released into an extremely harsh, highly variable and poorly understood environment. The ecological knowledge constraints were compounded by i) highly emotional species, ii) simultaneous and competitive projects, iii) logistic nightmare, iv) non-scientific basis in planning phase. By the late 1990s project leadership and management was overhauled with research and scientific data firmly integrated into the decision-making process. Early scientific input concentrated on determining causes of death and low reproductive rates. The elucidation of the effects of endemic piroplasmosis on the population and subsequent management changes lead to remediation this deadly problem. P-horses have been fitted with ARGOS and GPS-ARGOS collars in order to determine home range and habitat preferences. Simultaneously the Mongolian wild ass and the wolf have been studied with these methods in the shared habitat. Satellite-based technologies provide the backbone for all habitat related project issues. At the onset (digitized Russian maps) data collection was restricted to the Eastern part of the Gobi B. Subsequently the spatial scale encompasses the entire Gobi Region in Mongolia and Northern Xingjian in China (e.g. Landsat, MODIS, NOAA, SRTM). Research has also focused on the role, needs and possible impacts of local semi-nomadic herders that use the protected area. Capacity building and training workshops (e.g. construction of fuel efficient stoves, felting) have been initiated. In 2007 a trans-boundary project in collaboration with the Xingjian Institute of Ecology and Geography of the Chinese Academy of Sciences, was initiated. This project aims to support rural communities of nomadic pastoralists living in the trans-boundary area of the Dzungarian Gobi, in China and Mongolia. Today, this project and the one in Hustain Nuruu (Mongolia) are the only ones that have resulted in free-ranging non-supplemented populations. In the Gobi B area some 120 (status 05.2008) P-horses roam in the protected area. In 2003 the IUCN downlisted the Przewalski\'s horse from to . Further downlisting to is predicted to occur in 2011. There is no consensus on when a reintroduction program is deemed successful. Clearly viewing the self-sustainable re-establishment of a population as a successful end-point is at best a short-term approach, constrained by time (today and now). Comprehensive interdisciplinary monitoring and research was and is the foundation for management strategies and decisions in this project. However, a self-sustaining financial base in conjunction with dedicated training and empowerment of local scientists and residents constitute essential prerequisites for the project”s future. Defining success and thereby inferring an end-point can easily lead to complacency compromising species persistence. As others have stated the ultimate project objective must be a constantly re-evaluated state of population persistence without intervention.