Great tit (Parus major) breeding in fire-prone oak woods: differential effects of post-fire conditions on reproductive stages

Wildfires negatively affect the overall reproductive success of several woodland avian species, but there is scarce information about which stages of the nesting cycle are specifically affected. We conducted a 3-year study to identify the effects of fire on the reproductive parameters of the great tit (Parus major) and the survival of its nests at different stages of the nesting cycle. We recorded the occupancy rate, clutch and brood size, hatching, fledging and nesting success in nest boxes placed on study plots with different post-fire age. By examining the post-fire succession, we analysed the survival of eggs and nestlings under predation risks. As the forest matured after a wildfire, tits occupied more nest boxes and laid more eggs that suffered less predation than in earlier successional stages. Although the incubation fate improved at each step of succession, the conditions to fully raise nestlings seemed to be suitable only in the oldest woods. Our findings indicate that the population dynamics of a reputed generalist avian species may be affected by fire. Furthermore, the effects of wildfires on stage-specific reproductive parameters show that an avian species that inhabits woodlands regains its full productivity only when its habitat has completely recovered from fire

Diurnal habitat suitability for a Mediterranean steppeland bird, identified by Ecological Niche Factor Analysis

Context. The negative effects of agricultural intensification and policies, use of pesticides, fertilisers and mechanised harvesting on several populations of pseudo-steppe birds have increasingly required more detailed and effective habitat suitability models. Distribution models of farmland species are prone to incur recordings of false absence data. Ecological Niche Factor Analysis (ENFA) allows identification of environmental predictors of species distribution by using presence data only. Aims. We quantified the diurnal habitat preferences and niche width of one steppe species, the stone curlew (Burhinus oedicnemus), with unfavourable conservations status in a Mediterranean area and reclassified a map with respect to habitat suitability classes according to the resulting distribution model. Methods. Ecological Niche Factor Analysis was used with GIS cartography customised with habitat and anthropogenic variables recorded during field surveys carried out in four study plots (~500 ha) and at different spatial scales. Key results. The stone curlew selected areas with low vegetation cover, such as fields following artichoke harvesting and tillage, close to rural buildings and unpaved roads. In contrast, the stone curlew avoided areas with high vegetation cover and areas highly disturbed by human-induced fires. The occurrence of natural vegetation was neither preferred nor avoided. The most robust model was based on a large-scale analysis (200mfrom the bird location points), according to which the optimal area for stone curlew distribution during its breeding season was restricted to 1% of the entire study area. Conclusions. Two uncorrelated factors, ‘marginality’ and ‘tolerance’, described the stone curlew’s niche in the area. The first index indicated selection for habitats that were marginal with respect to those available in the area, whereas the second indicated a species with a medium–wide environmental niche. In particular, the stone curlew occupied a much more restricted niche (low tolerance) in relation to individual variables. The use of customised databases at a large scale of analysis was found to more effectively reveal ecological requirements of this marginal and specialised species. Implications. Our results allowed us to indicate practical land management actions for the stone curlew, such as prevention of human-induced fires and increase of pastoral activities. Our results indicated a potentially positive role of littledisturbed service roads along rural buildings in stone curlew distribution, which warrants further research. In addition, studies are needed to verify the presence of an ecological trap in artichoke fields, their preferred habitat. As we showed for the stone curlew, niche analyses conducted at a large scale using customised databases could greatly improve habitat suitability models of farmland species

Nest aggregation and reproductive synchrony promote Lesser Kestrel Falco naumanni seasonal fitness

Several factors promote coloniality by enhancing the fitness of colony members. In birds, spatial proximity among nests, breeder abundance and reproductive synchrony have been proposed as primary factors responsible for enhanced colonial defence and foraging success, which, in turn, enhance reproductive success. Whether these factors function synergistically or antagonistically remains, however, an open question due to the absence of an integrated analysis of their effects on fitness. We studied a large population of the Lesser Kestrel, Falco naumanni, a facultative colonial species, breeding in colonies of different sizes in their typical pseudo-steppe habitat. We quantified both the singular and interactive effects of nest distance, breeder abundance and reproductive synchrony on kestrel fitness measured as the time to survival of eggs to hatching and nestlings to fledging. Egg survival increased as reproductive stages became more synchronous with the timing of colony breeding, whereas nestling survival benefited from a higher synchrony with most nests in the entire population. Nestling survival was also positively affected by the interaction between nest distance and breeder abundance. Our results suggest that the presence of additional breeders in the colony is not sufficient per se, to trigger colonial advantages, but instead, that synchronised reproduction among multiple breeding pairs nesting in close spatial proximity is necessary to realise those benefits. Our findings provide a novel perspective for future investigations that explore the mechanisms underlying fitness variation among Lesser Kestrel colonies and group-living species in genera

Food for flight: pre-migratory dynamics of the Lesser Kestrel Falco naumanni.

Capsule The post-reproductive stage of Lesser Kestrel is crucial for migratory fuelling and survival. Aims To describe the summer pre-migratory ecology of the Lesser Kestrel in Sicily and review existing data in Southern Europe. Methods We identified the main summer roosts and then made roost counts every ten days from 2010 to 2012. We used case-sensitive modelling procedures to detect biases in counts (generalized linear mixed models), assess the annual population trends from 2005 to 2012 (TRends and Indices for Monitoring); and to model habitat preferences (generalized linear model). We sampled pellets to describe the birds’ diet during the peak month prior to migration. Results We discovered five roosts in Sicily with numbers of Lesser Kestrels varying annually (mean ±sd: 2112±387; min–max: 1797–2544). Counts at the main roost were not biased by meteorological conditions and showed an August peak followed by persistent decline through October. Less urbanized and heterogeneous agricultural areas with large cereal fields were the most significant habitats preferred during summer. Within this landscape, Lesser Kestrels prey on seasonally high concentrations of the small cricket Grylloderes brunneri. Conclusion Arable land not fragmented by agricultural intensification supports habitat rich with Orthopterans and attracts a large number of Lesser Kestrels fuelling before migration. Conservation of such pre-migratory habitats is as vital as conservation of breeding areas

Changes in behavioural response of Mediterranean Seabass (Dicenthratus labrax L.) under different feeding distributions

Captive-induced behavioural deviations may involve many aspects of fish behaviour such as swimming activity and enhancement of individual aggressiveness. We studied seabass (Dicentrarchus labrax) behaviour as a function of manual and automatic feeding distribution modes. Under manual mode, the food is distributed over an extended area for a longer period, and its precise location is not always predictable, while with pneumatic automatic feeders, fish receive the same amount of resource, which is concentrated in the same surface area over a shorter period. We compared seabass behaviour under automatic and manual conditions collecting video image recordings before, during, and after feeding distribution, in the morning and in afternoon, on two different days, and analysing data within independent sessions of measurements. Feeding modes significantly affected swimming behaviour: automatically- fed fish were characterised by vertical movements through the water column (towards the surface and bottom) and by horizontal swimming. Manually-fed fish were instead characterised by sharp direction changes during their swimming, mostly towards the surface. Feeding distribution induced changes in collision frequency and elicited aggressive behaviour. In particular, agonistic behaviour (i.e. a fish attacks another fish) was almost exclusively recorded during the feeding under automatic distribution, whereas it was constantly expressed during all the distribution phases under manual mod

Planning conservation actions by investigating nest preferences and biotic and abiotic factors within lesser kestrel (Falco naumanni) colonies

The lesser kestrel (Falco naumanni) was until recently classified as a Vulnerable species. It is a cavity nester species finding proper nest sites in natural cliff holes or, as more frequently today, cavities found within rural buildings. These are often abandoned and therefore, with no maintenance, the main structures of kestrel colonies have been collapsing across years. To counterbalance the reduced availability of nesting sites for kestrels, and because of their unfavorable conservation status, artificial nest boxes have been placed in several areas of their breeding range. On our study site, the Gela Plain in Sicily, as on other Mediterranean breeding areas, high temperatures may reach lethal values for the nest content. Since 2004, we collected biotic and abiotic data at macro- and micro-scales to integrate an analysis aiming to predict nest temperatures in different nest types. Paradoxically, early breeders preferentially occupied the coolest nest types, the roof tiles, whereas late breeders, starting their nesting attempts with hotter temperatures, occupied the overheated nest boxes. We discuss our findings in the light of planning proper and efficient conservation actions, such as providing different nest types, by pondering whether kestrel nest preferences might either sort into ecological traps or be the result of ecological limitations

Effects of nautical traffic and noise on foraging patterns of Mediterranean damlsefish (Chromis chromis)

Chromis chromis is a key species in the Mediterranean marine coastal ecosystems where, in summer, recreational boating and its associated noise overlap. Anthropogenic noise could induce behavioural modifications in marine organisms, thereby affecting population dynamics. In the case of an important species for the ecosystem like C. chromis, this could rebound on the community structure. Here, we measured nautical traffic during the summer of 2007 in a Southern Mediterranean Marine Protected Area (MPA) and simultaneously the feeding behaviour of C. chromis was video-recorded, within both the no-take A-zone and the B-zone where recreational use is allowed. Feeding frequencies, escape reaction and school density were analysed. C. chromis specimens were also collected from 2007 to 2008 to evaluate their physiological state using the Body Condition Index as a proxy of feeding efficiency. The MPA was more exploited by nautical tourism during holidays than on weekdays, particularly in the middle of the day. Greater traffic volume corresponded with lower feeding frequencies. The escape reaction was longer in duration (>1 min) when boat passed nearby, while moored boats did not induce an escape response. We found no differences in density between schools in the A- and B-zones and worse body conditions among those individuals inhabiting the B-zone in one area only. Overall, our findings revealed a significant modification of the daily foraging habits of C. chromis due to boat noise, which was slightly buffered by no-take zones established within the MPA