Sex Allocation in Relation to Host Races in the Brood-Parasitic Common Cuckoo (Cuculus canorus)

Sex allocation theory and empirical evidence both suggest that natural selection should favour maternal control of offspring sex ratio in relation to their ability to invest in the offspring. Generalist parasites constitute a particularly interesting group to test this theory as different females commonly utilize different host species showing large variation in provisioning ability. The common cuckoo (Cuculus canorus) is a generalist brood parasite that lays its eggs in the nest of many different passerine birds, but each female tends to specialize on one particular host species giving rise to highly specialized host races. The different host species show large variation in their ability to invest in the parasitic offspring, presenting an opportunity for female cuckoos to bias offspring sex ratio in relation to host species quality. Here, we investigate host-race specific sex allocation controlling for maternal identity in the common cuckoo. We found no evidence of any significant relationship between host race and sex ratio in one sympatric population harbouring three different host races, or in a total of five geographically separated populations. There was also no significant association between host quality, as determined by species-specific female host body mass, and cuckoo sex ratio. Finally, we found no significant relationship between individual cuckoo maternal quality, as determined by her egg volume, and sex ratio within each host race. We conclude that the generalist brood-parasitic common cuckoo show no significant sex-ratio bias in relation to host race and discuss this finding in light of gene flow and host adaptations

Are Cuckoos Maximizing Egg Mimicry by Selecting Host Individuals with Better Matching Egg Phenotypes?

Background: Avian brood parasites and their hosts are involved in complex offence-defense coevolutionary arms races. The most common pair of reciprocal adaptations in these systems is egg discrimination by hosts and egg mimicry by parasites. As mimicry improves, more advanced host adaptations evolve such as decreased intra- and increased interclutch variation in egg appearance to facilitate detection of parasitic eggs. As interclutch variation increases, parasites able to choose hosts matching best their own egg phenotype should be selected, but this requires that parasites know their own egg phenotype and select host nests correspondingly. Methodology/Principal Findings: We compared egg mimicry of common cuckoo Cuculus canorus eggs in naturally parasitized marsh warbler Acrocephalus palustris nests and their nearest unparasitized conspecific neighbors having similar laying dates and nest-site characteristics. Modeling of avian vision and image analyses revealed no evidence that cuckoos parasitize nests where their eggs better match the host eggs. Cuckoo eggs were as good mimics, in terms of background and spot color, background luminance, spotting pattern and egg size, of host eggs in the nests actually exploited as those in the neighboring unparasitized nests. Conclusions/Significance: We reviewed the evidence for brood parasites selecting better-matching host egg phenotypes from several relevant studies and argue that such selection probably cannot exist in host-parasite systems where hos

Community spatial distance and educational determinants of how local people appreciate conservation benefits around Tarangire and Saadani National Parks, Tanzania

The understanding of how educational and spatial factors influence appreciation of conservation benefits to locals living adjacent to protected areas is a very important aspect in conservation initiatives. In this study we compared how educational and spatial factors affect the appreciation of conservation benefits to local communities adjoining the two Tanzanian national parks; Tarangire National Park (TNP) and Saadani National Park (SANAPA). Questionnaire surveys including closed-ended questions were conducted in eight villages, four near each of the two parks. A total of 400 randomly selected households were interviewed (50 in each village). Results from these questionnaires showed that the local people’s appreciation of benefits was negatively related to increasing distance from the parks boundaries. Moreover, people with secondary education or higher, appreciated to receive more benefits than those with primary and tended to appreciate benefits more often than those with no formal education. In addition, people living around TNP responded that the park itself benefited more in terms of benefits from tourism compared to communities surrounding SANAPA. The underlying mechanisms for establishing strong relationships, e.g., by initiating conservation benefits close to national parks, is key to improve views on conservation practices from local people surrounding national parks

GPS-loggers influence behaviour and physiology in the black-legged kittiwake Rissa tridactyla

International audienceIn recent decades, data loggers and radio- and satellite transmitters have become an important technological part of research on free living animals. Loggers to track movements and behaviour are especially useful in seabird studies, as seabirds often travel considerable distances at sea where visual observations are challenging. The potential negative effects of these devices on mortality, behaviour and reproduction of birds have received some attention, but few studies have investigated the physiological effects of instrument attachment. In the present study, effects of global positioning system (GPS) loggers on black-legged kittiwakes Rissa tridactyla were investigated by obtaining behavioural and physiological parameters of stress (nest attendance, plasma levels of the avian stress hormone corticosterone [CORT], relative leucocyte counts, body mass and reproductive success) during 2 d of GPS-deployment. GPS-equipped kittiwakes had significantly elevated levels of CORT at recapture and also significantly extended the duration of feeding trips compared to controls. Kittiwakes with low body condition index (BCI) attended nests less than controls, and this pattern was more pronounced among GPS-equipped birds. The study underlines the need to take device effects into consideration when instrumenting seabirds. Potentially, effects may become more evident in birds with low body condition or in years where food is limited, and results from GPS-equipped birds should be viewed with this in mind

Drivers of conservation crimes in the Rungwa-Kizigo-Muhesi Game Reserves, Central Tanzania

Conservation crimes are posing serious threats to wildlife species and biodiversity of the Rungwa-Kizigo-Muhesi-Game-Reserves. Devising effective strategies to reduce risks to as low as reasonably possible of these crimes, calls for adequate information on factors driving people to commit these crimes. Data for this study were obtained from 315 respondents in 20 villages and 316 people who were arrested for committing different conservation crimes in the Rungwa-Kizigo-Muhesi-Game-Reserves. Our results suggest that arrested respondents were typically young adult males with limited alternative sources of income and owning virtually no livestock or land. There were heterogeneous drivers for each type of conservation crime. To address the challenge of conservation crimes in the Reserve, we recommend, among other strategies, the establishment of effective conservation education programmes, strengthening law enforcements as a deterrence method, and development of entrepreneurship skills to enhance employment. Keywords: Bushmeat poaching, Conservation criminology, Elephant, Illegal timber logging, Wildlife poachin

Diurnal and nocturnal movements of Kori Bustards in the Serengeti ecosystem

publishedVersio

Morphological data

Data containing morphological measurements of house sparrows in 11 islands of the Helgeland archipelago in Northern Norway

Data from: Characterizing morphological (co)variation using structural equation models: body size, allometric relationships and evolvability in a house sparrow metapopulation

Body size plays a key role in the ecology and evolution of all organisms. Therefore, quantifying the sources of morphological (co)variation, dependent and independent of body size, is of key importance when trying to understand and predict responses to selection. We combine structural equation modeling with quantitative genetics analyses to study morphological (co)variation in a meta-population of house sparrows (Passer domesticus). As expected, we found evidence of a latent variable ‘body size’, causing genetic and environmental covariation between morphological traits. Estimates of conditional evolvability show that allometric relationships constrain the independent evolution of house sparrow morphology. We also found spatial differences in general body size and its allometric relationships. On islands where birds are more dispersive and mobile, individuals were smaller and had proportionally longer wings for their body size. While in islands where sparrows are more sedentary and nest in dense colonies, individuals were larger and had proportionally longer tarsi for their body size. We corroborated these results using simulations and show that our analyses produce unbiased allometric slope estimates. This study highlights that in the short term allometric relationships may constrain phenotypic evolution, but that in the long term selection pressures can also shape allometric relationships

Data from: Demographic influences of translocated individuals on a resident population of house sparrows

Translocation of individuals from source populations to augment small populations facing risk of extinction is an important conservation tool. Here we examine sex-specific differences between resident and translocated house sparrows Passer domesticus in reproductive success and survival, and the contribution of translocated individuals to the growth of a local population. We found evidence for assortative mating based on origin revealed by fewer parentages between translocated males and resident females than expected, and the total number of fledglings produced by such pairs was lower. Interestingly, the reproductive success of translocated males was positively related to the size of the throat badge (a sexual ornament), such that translocated males with a large badge size were as successful as resident males. However, offspring with parents of different origin had higher survival than offspring with parents of same origin, which suggests hybrid vigour. The contribution of resident and translocated individuals to the stochastic component of the long-run growth rate of the population was similar; neither the mean individual contributions in fitness nor the demographic variance differed between the two groups. Thus, this experiment shows that translocated individuals may have a similar demographic influence on the growth of local populations as resident individuals. Still, the intermixing of translocated and resident individuals was low, and fitness differed according to origin in relation to individual differences in a sexually selected trait. In addition, hybrid vigour with respect to offspring recruitment seemed to partially relax the negative fitness consequences of the assortative mating based on origin