Grünau im Almtal, Austria
Grünau im Almtal, Austria

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Ludwig S.C.,Institute of Avian Research Vogelwarte Helgoland | Ludwig S.C.,Konrad Lorenz Research Station | Becker P.H.,Institute of Avian Research Vogelwarte Helgoland
Ibis | Year: 2012

Mating between close relatives can have deleterious effects on reproductive success or offspring fitness, which should favour the evolution of active or passive inbreeding avoidance mechanisms. In birds, evidence for active inbreeding avoidance by kin-discriminative mate choice is scarce; many studies describe random mating in relation to kinship and thus support passive inbreeding avoidance by natal dispersal. However, most studies were conducted in island populations of short-lived passerines with fast alternation of generations. In this study, we present inbreeding estimates based on pedigree data from a 16-year study in a coastal colony of Common Terns Sterna hirundo, a long-lived seabird with delayed sexual maturation and low rates of extra-pair paternity. Incestuous mating was rare (four of 2387 pairs), even if partially accounting for incomplete pedigrees. Although the average relatedness of observed pairs was lower than would be expected from random pairing, the inbreeding coefficient did not differ from random mating. Hence, we found no clear evidence for active inbreeding avoidance by kin-discriminative mate choice, and the low level of inbreeding seems to be related to the high immigration rate in the colony and thus to be maintained passively by dispersal. © 2011 The Authors. Ibis © 2011 British Ornithologists' Union.


Dufour V.,University of Strasbourg | Dufour V.,French National Center for Scientific Research | Wascher C.A.F.,Konrad Lorenz Research Station | Wascher C.A.F.,University of Vienna | And 5 more authors.
Biology Letters | Year: 2012

Evidence for time-dependent calculations about future rewards is scarce in non-human animals. In non-human primates, only great apes are comparable with humans. Still, some species wait for several minutes to obtain a better reward in delayed exchange tasks. Corvids have been shown to match with non-human primates in some time-related tasks. Here, we investigate a delay of gratification in two corvid species, the carrion crow (Corvus corone) and the common raven (Corvus corax), in an exchange task. Results show that corvids success decreases quickly as delay increases, with a maximal delay of up to 320 s (more than 5 min). The decision to wait rests both on the quality of the prospective reward and the time required to obtain it. Corvids also apply tactics (placing the reward on the ground or caching it) that probably alleviate costs of waiting and distract their attention during waiting. These findings contrast previous results on delayed gratification in birds and indicate that some species may perform comparably to primates.© 2011 The Royal Society.


Martinez-Padilla J.,CSIC - National Museum of Natural Sciences | Martinez-Padilla J.,University of Aberdeen | Vergara P.,CSIC - National Museum of Natural Sciences | Vergara P.,University of Aberdeen | And 10 more authors.
Biology Letters | Year: 2011

In many species, females display brightly coloured and elaborate traits similar to those that males use in intra- and inter-sexual selection processes. These female characters are sometimes related to fitness, and might function as secondary sexual characteristics that have evolved through sexual selection. Here, we used descriptive data from 674 females in 10 populations and an experimental removal of Trichostrongylus tenuis parasites in four populations, to examine the effects of season, age, condition, and parasites on the size of supraorbital combs displayed by female red grouse Lagopus lagopus scoticus. We found that comb size (i) was greater during the breeding than the non-breeding season, (ii) was greater in adult than in young females, (iii) was positively correlated with body condition, and (iv) negatively correlated with parasite abundance. Experimentally, we showed that comb size increased proportionally to the number of worms removed after parasite dosing. Our findings provide a better understanding of proximate mechanisms behind the expression of a male-like trait in females, and we discuss its possible function as a female ornament. © 2010 The Royal Society.


Sim I.M.W.,Royal Society for the Protection of Birds RSPB Scotland | Sim I.M.W.,University of Aberdeen | Ludwig S.C.,Royal Society for the Protection of Birds RSPB Scotland | Ludwig S.C.,Konrad Lorenz Research Station | And 4 more authors.
Auk | Year: 2013

Recent evidence suggests that avian population growth rates may be constrained by low postfledging survival. Therefore, quantifying postfledging mortality and understanding the ecological factors that influence it are fundamental for assessing the relative importance of this life-history stage for population growth and identifying the ecological drivers of population dynamics. We radiotracked 110 juvenile Ring Ouzels (Turdus torquatus), a species of high conservation concern in the United Kingdom, to test hypotheses regarding the timing and causes of postfledging mortality and to quantify the timing and magnitude of local movements and dispersal. Juveniles fledged from early-season broods had higher survival during each 4-day period over 116 days postfledging (0.952 ± 0.011 [SE]) than juveniles fledged from late-season broods (0.837 ± 0.021). Most mortality occurred within the first 3 weeks postfledging, and predation by raptors and mammals was the main apparent cause of mortality, accounting for 59% and 27% of deaths, respectively. Juvenile survival decreased at the age of independence from parental care. Juveniles traveled increasing distances from their nests with time after fledging, and those that fledged early in the season dispersed outside the study area at significantly older ages than those that fledged late in the season. Copyright © 2013 by The American Ornithologists' Union.


Ujfalussy D.J.,Eötvös Loránd University | Miklosi A.,Eötvös Loránd University | Bugnyar T.,Konrad Lorenz Research Station | Bugnyar T.,University of Vienna
Animal Cognition | Year: 2013

The aim of the present study was to investigate the ontogeny of object permanence in a non-caching corvid species, the jackdaw (Corvus monedula). Jackdaws are often presented as typical examples of non-storing corvids, as they cache either very little or not at all. We used Uzgiris and Hunt's Scale 1 tasks to determine the age at which the certain stages set in and the final stage of this capacity that is reached. Our results show that the lack of food-storing behaviour is not associated with inferior object permanence abilities in the jackdaw, as our subjects (N = 19) have reached stage 5 competence (to follow successive visible displacements) at the average age of 61 days post-hatch and showed some evidence of stage 6 competence (to follow advanced invisible displacements) at 81 days post-hatch and thereafter. As we appreciate that object permanence abilities have a very wide ecological significance, our positive results are probably the consequence of other, more fundamental ecological pressures, such as nest-hole reproduction or prey-predator interactions. © 2012 Springer-Verlag Berlin Heidelberg.


Hirschenhauser K.,Konrad Lorenz Research Station | Weiss B.M.,Konrad Lorenz Research Station | Haberl W.,Hamburgerstrasse 11 | Mostl E.,University of Vienna | Kotrschal K.,Konrad Lorenz Research Station
General and Comparative Endocrinology | Year: 2010

For successfully raising offspring, long-term monogamous pair partners need to be behaviorally and hormonally coordinated. In the monogamous, biparental greylag geese (Anser anser) a dyadic pairbond-specific measure, 'within-pair testosterone compatibility' (TC) indicated how closely synchronized are seasonal androgen levels, which co-varied with reproductive output. Males, in particular, were assumed to respond to their females' hormonal and fecundity phases. We now present experiments with biparental domestic geese (Anser domesticus) kept as pairs to ask whether TC occurs also in these generally polygynous animals. We further ask how different conditions of mate choice affect TC and whether established TC is maintained during a polygynous flock situation. We measured androgen metabolites (AM) non-invasively from individual droppings. In females, AM was related with gonadal activity as it increased after GnRH but not ACTH challenge. Females with preferred partners had higher maximum AM during egg laying and higher rates of initiating incubation than randomly paired females. Domestic ganders had seasonal AM patterns typical for polygynous males. Within-pair TC ranged from almost perfectly positive to non-correlated in domestic geese but mate choice did not explain TC variation. TC of previous pairs was generally reduced in the flock situation, probably confounded by factors of the social environment, i.e. mating opportunity and availability of multiple partners. On top of the underlying reproductive physiology our results suggest two episodic components of TC: a female androgen responsiveness to the preferred partner at least during egg formation, and the male's facultative potential to respond to her readiness to breed. © 2009 Elsevier Inc. All rights reserved.


Kenward B.,University of Oxford | Schloegl C.,Konrad Lorenz Research Station | Schloegl C.,German Primate Center | Rutz C.,University of Oxford | And 4 more authors.
Biological Journal of the Linnean Society | Year: 2011

New Caledonian crows (Corvus moneduloides) are prolific tool users in captivity and in the wild, and have an inherited predisposition to express tool-oriented behaviours. To further understand the evolution and development of tool use, we compared the development of object manipulation in New Caledonian crows and common ravens (Corvus corax), which do not routinely use tools. We found striking qualitative similarities in the ontogeny of tool-oriented behaviour in New Caledonian crows and food-caching behaviour in ravens. Given that the common ancestor of New Caledonian crows and ravens was almost certainly a caching species, we therefore propose that the basic action patterns for tool use in New Caledonian crows may have their evolutionary origins in caching behaviour. Noncombinatorial object manipulations had similar frequencies in the two species. However, frequencies of object combinations that are precursors to functional behaviour increased in New Caledonian crows and decreased in ravens throughout the study period, ending 6weeks post-fledging. These quantitative observations are consistent with the hypothesis that New Caledonian crows develop tool-oriented behaviour because of an increased motivation to perform object combinations that facilitate the necessary learning. © 2011 The Linnean Society of London.


Schloegl C.,Konrad Lorenz Research Station | Schloegl C.,University of Vienna
Journal of Comparative Psychology | Year: 2011

Choice by exclusion, that is, the ability to base the choice of a target on the rejection of potential alternatives, is becoming increasingly interesting for comparative cognition research. Recently, ravens have been shown to solve an exclusion task and it had been suggested that this ability might benefit ravens in a food-caching context. To investigate this possibility, the raven study was replicated with a closely related, but noncaching, species, the jackdaw (Corvus monedula). In the first test, the birds had to find food hidden in one of two differently shaped tubes. The results suggest that the jackdaws found the food through intensive search behavior, with little evidence for exclusion abilities. In a follow-up experiment, the tubes were replaced by cups, and before the birds made a choice, one of the cups was lifted to inform them about its content. In a final task, this procedure was modified to control for the influence of local enhancement. In both experiments, the jackdaws were successful only if they had seen the food before. These findings are in contrast to the previous results on ravens and support the idea that exclusion abilities may have evolved as specific adaptations to food caching. © 2011 American Psychological Association.


Ujfalussy D.J.,Eötvös Loránd University | Miklosi A.,Eötvös Loránd University | Bugnyar T.,Konrad Lorenz Research Station | Bugnyar T.,University of Vienna | Kotrschal K.,University of Vienna
Journal of Comparative Psychology | Year: 2014

The representation of quantity by the preverbal or nonverbal mind is a question of considerable interest in the study of cognition, as it should be generally adaptive to most animals to be able to distinguish quantity. We already know that some primate species and human infants represent and enumerate objects in similar ways. Considerable data also exist concerning such abilities in birds. Our aim in this study has been to find out whether jackdaws (Corvus monedula) are capable of performing relative quantity judgments based on mental representations, and if so, what are the limiting factors to their abilities. In our setting the birds were required to make a choice between two visibly and sequentially placed set of food items which, at the moment of choice were not visible to the subjects. We investigated all the number combinations between 1 and 5. Our results show that jackdaws are able to perform relative quantity judgments successfully, even when temporal cues are controlled for, whereas their performance declines in the direction of larger set size (numerical size effect), and when the difference between the two arrays decreases (numerical distance and ratio effect). These signatures are usually interpreted as evidence for the "accumulator" model of mental representation of quantity. Our control results suggest that jackdaws do not use temporal cues, but may well use total volume as basis for discrimination, perhaps among other attributes (choice may be based on multiple cues). © 2013 American Psychological Association.


PubMed | Konrad Lorenz Research Station and University of Oxford
Type: Journal Article | Journal: Biological journal of the Linnean Society. Linnean Society of London | Year: 2015

New Caledonian crows (

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