The influence of visitor interaction on the behavior of captive crowned lemurs (Eulemur coronatus) and implications for welfare.

Research suggests that zoo visitors can have positive, negative, and neutral impacts on captive primate welfare; however, research investigating the implications of visitor-animal feeding experiences is extremely limited. In the UK, a large proportion of BIAZA zoos that house lemur species offer visitor interaction experiences (16 out of 33). This study investigated the impact on the behavior of a family group of crowned lemurs (Eulemur coronatus) housed at Newquay Zoo, UK of visitors, accompanied by a keeper, entering the enclosure to feed the lemurs. Behavior was observed under four conditions: (i) during visitor feed; (ii) 30 min post-visitor feed; (iii) during a keeper feed; and (iv) 30 min post-keeper feed. Keeper feeds were conducted by keepers only, on the day after visitor feeds. The lemur group spent significantly less time performing aggressive behavior and was also significantly more interactive with keepers during visitor feeds compared with keeper-only feeds. There was no significant difference in behaviors performed immediately after interacting with visitors. Over the study period, there was a tendency for interactions with visitors to increase, and for interactions with keepers during visitor feeds to decrease. After a 28-day interval without visitor interaction, the lemurs' interaction with visitors had returned to the level recorded at the start of the study. In conclusion, visitor interaction did not compromise the welfare of the study subjects in either the short- or long-term, while an increase in visitor interactions over time has interesting implications for the enrichment properties of, or habituation to, unfamiliar humans. Zoo Biol. 35:222-227, 2016. © 2016 Wiley Periodicals, Inc.

Do great tits assess rivals by combining direct experience with information gathered by eavesdropping?

Animals frequently use signals that travel further than the spacing between individuals. For every intended recipient of a given signal there are likely to be many other individuals that receive information. Eavesdropping on signalling interactions between other individuals provides a relatively cost-free method of assessing future opponents or mates. Male great tits (Parus major) extract relative information from such interactions between individuals unknown to them. Here, we show that male great tits can take information gathering a stage further and obtain more information about a previously unencountered intruder, by the hitherto unknown capability of combining information gathered by eavesdropping with that derived from their own direct interaction with an individual. Prior experience with an intruder (A) was achieved by subjecting a focal male to different levels of intrusion simulated using interactive playback. This intruder (A) then took part in a simulated interaction with an unknown male (B) outside the territorial boundary of the focal males. In response to subsequent intrusion by the second male (B), focal males showed low song output in response to males that had lost to a male that the subject was able to beat. Males of known high quality, or those about which information was ambiguous, elicited a high level of song output by focal males. We discuss the implications of this finding for the evolution of communication and social behaviour.

Male great tits eavesdrop on simulated male-to-male vocal interactions.

Animal communication generally occurs in the environment of a network of several potential signallers and receivers. Within a network environment, it is possible to gain relative information about conspecifics by eavesdropping on signalling interactions. We presented male great tits with the opportunity to gain such information by simulating singing interactions using two loudspeakers. Interactions were presented so that relevant information was not available in the absolute singing behaviour of either individual, only in the relative timing of their songs in the interaction as a whole. We then assayed the information extracted by focal males by subsequently introducing one of the 'interactants' (i.e. loudspeakers) into the territory of the focal male. Focal males responded with a reduced song output to males that had just 'lost' an interaction. Focal males did not respond significantly differently to 'winners' as compared with intruders recently involved in an interaction that contained no consistent information. Focal males also responded by switching song types more often when encountering males that had recently been involved in a low-intensity interaction. These results provide the clearest evidence yet that male songbirds extract information from signal interactions between conspecifics in the field.

Conditioning pigeons to discriminate naturally lit insect specimens.

Pigeons (Columba livia) were trained on a visual discrimination task using a novel apparatus which enabled pinned specimens of insects, illuminated by natural daylight, to be presented under a pecking key transparent to ultraviolet light. Three birds showed evidence of learning to discriminate between sets of wasp and fly specimens. This response transferred to specimens of four hoverfly species, the strength of the response varying between the different hoverfly species. This conditioning technique offers a promising means of analysing mechanisms of visual processing in birds that are relevant to theories of the evolution of camouflage and mimicry.

The prevalence and intensity of infection with helminth parasites in Mus spretus from the Setubal Peninsula of Portugal.

The results of a 5 year study of helminth parasites of Mus spretus, are reported. Six nematode and 5 cestode species were identified but no helminth showed 100% prevalence in M. spretus, the most commonly encountered nematode and cestode species being Syphacia obvelata (46.6%) and Taenia taeniaeformis (22.4%). Among the more unusual helminth species identified was Eucoleus bacillatus, a capillariid nematode inhabiting the stomach musculature. This species was identified in 3 of the 5 years of the study. The results are discussed in the broader context of previous studies and the epidemiology of rodent helminth infections in general.

Discrimination of song types by male great tits.

The purposes of this study were: to test whether male song birds could be trained to discriminate between a reference song type and a set of other types and to see if in learning the discrimination the birds had formed a category of "reference song" as opposed to "others". Three male great tits learned to discriminate between a reference song type (B) and 10 others. All of them showed an improvement with experience, although the final scores and consistency varied between individuals. In spite of the variability among birds some of the 10 song types were easier to discriminate from B than others. Two of the birds achieved at least 80% of discrimination, but only one of them yielded good data in the following categorization tests: In one session the bird was presented with 20 novel "other" song types and the same reference type B. This bird treated all 20 types as "others". Therefore, the bird appears to have formed the category "other". In two other sessions the bird was presented with 40 different versions of B (as classified by the authors) recorded from 40 different individual birds, and the same 10 training "others". The bird categorized 16 out of the 40 Bs as B, and overall discriminated significantly between Bs and the 10 other types. Therefore, this bird generalized the stimulus song B to other related stimuli. We conclude that, although our results are preliminary, they at least indicate a method of studying how birds categorize songs.