Emberiza Hortulana Research Articles

Habitat characteristics and the rate of decline in a threatened farmland bird, the ortolan bunting Emberiza hortulana

Farmland habitats witness steep declines in biodiversity. One rapidly declining farmland species is the ortolan bunting Emberiza hortulana. In Finland, a staggering 99% of the population has been lost during the past 30 years. Changes in the breeding habitats have been proposed as a reason for the decline, although hazards during migration and wintering may also play a role.We gathered a 19‐year data set of Finnish ortolan buntings and studied which spatial characteristics, habitat features, and climate factors might explain the population growth rate at the singing‐group level. As explanatory variables we used region, density of small‐scale structures, proportion of agricultural area in the landscape, diversity of crop types, proportion of bare ground, and temperature and precipitation of previous breeding season.Higher population growth rates were associated with higher crop type diversity and higher proportion of bare ground. The mosaic of various crop plants and bare ground may provide a wider array of feeding, hiding and nesting places, and an easier access to food. Higher growth rates were also associated with landscapes dominated by interconnected agricultural land, which may reflect the species' sociability and avoidance of forested areas. The North Ostrobothnia region had higher growth rates compared to other regions.We suggest that northern populations of ortolan bunting should be targeted for further studies on feeding and breeding ecology as well as for urgent conservation actions, such as increasing crop type diversity and bare ground.

New data on the nesting of the ortolan bunting Emberiza hortulana Linnaeus, 1758 in the Algerian Aures mountains

New data on the nesting of the ortolan bunting Emberiza hortulana Linnaeus, 1758 in the Algerian Aures mountains

Traditional landscape elements are key to the threatened Ortolan Bunting Emberiza hortulana in its Italian stronghold

ABSTRACT Capsule Cultural landscapes with Tamarisk Tamarix gallica rows, marginal habitats and crop heterogeneity promote the occurrence of Ortolan Buntings Emberiza hortulana in the Marche region, a key area for the species’ conservation in Italy. Aims To evaluate the land-use determinants of the occurrence of the Ortolan Bunting, a species strikingly declining in recent decades. Methods Within the Marche region, the Italian stronghold of the species, we surveyed 20 plots in the hilly belt of Pesaro-Urbino province, and recorded different potential land-cover drivers of the occurrence of Ortolan Buntings. We modelled habitat selection according to environmental variables measured in the field at an equal number of territory and control sites, using generalized linear models. Results We found 104 territories of Ortolan Buntings. Different groups of predictors (crop cover, marginal habitats, other land-uses) were similarly important; positive drivers of the species’ occurrence were the covers of cereal, dead trees, pure and mixed Tamarisk rows, other crops, sunflower, and reeds; covers of broom had a quadratic effect, while negative effects were found with seminatural grassland, paved roads, and isolated shrubs. The disappearance of cultural landscapes, which is ongoing in many European areas, resulted in the loss of elements typically found in low-intensity farming systems and of particular importance for the species. Tamarisk rows may provide multiple benefits, offering song posts and potential nesting sites close to the ground, and their abundance in the Marche region could contribute to explain why Ortolan Buntings are locally more common there, compared to other Italian regions. Conclusions The maintenance of Tamarisk rows, marginal habitats and crop heterogeneity are key measures needed to support Ortolan Bunting populations.

Will passive acoustic monitoring make result‐based payments more attractive? A cost comparison with human observation for farmland bird monitoring

AbstractResult‐based payments (RBPs) reward land users for conservation outcomes and are a promising alternative to standard payments, which are targeted at specific land use measures. A major barrier to the implementation of RBPs, particularly for the conservation of mobile species, is the substantial monitoring cost. Passive acoustic monitoring may offer promising opportunities for low‐cost monitoring as an alternative to human observation. We develop a costing framework for comparing human observation and passive acoustic monitoring and apply it to a hypothetical RBP scheme for farmland bird conservation. We consider three different monitoring scenarios: daytime monitoring for the whinchat and the ortolan bunting, nighttime monitoring for the gray partridge and the common quail, and day‐and‐night monitoring for all four species. We also examine the effect of changes in relevant parameters (such as participating area, travel distance and required monitoring time) on the cost comparison. Our results show that passive acoustic monitoring is still more expensive than human observation for daytime monitoring. In contrast, passive acoustic monitoring has a cost advantage for nighttime as well as day‐and‐nighttime monitoring in all considered scenarios.

Lone male loser? Effects of spatial isolation on male pairing success in the Ortolan Bunting (Emberiza hortulana)

Cover photo: Male Ortolan Bunting. Photo: Frode Falkenberg. In small, isolated or fragmented bird populations, past studies have shown that there can be a high proportion of unpaired males. Low male pairing success is suggested to be the result of female-biased natal dispersal and low female recruitment. Indirect evidence indicates that such an effect operates among populations with different degrees of isolation, but little is known of how isolation affects male pairing success within populations. The Norwegian population of Ortolan Buntings (Emberiza hortulana) is distributed in about 50 discrete patches in an area of nearly 500 km2. In this study, we examined whether patch isolation and individual male isolation affected male pairing success. The population has a strongly male-biased sex ratio, with almost half of all males being unpaired. We found that male pairing successs was negatively related to isolation of patches and isolation of individual males in most analyses, and with significant effects in particular in some analyses of individual isolation. Patch population size was measured as the total number of males observed in a particular patch in a specific year and did not have an effect on male pairing success, and was not related to patch isolation. Even though some tests were statistically significant, the magnitude of effects were small and there was large variance in male pairing success. Variance in success suggests that other factors than isolation such as male age or experience may be just as important for male fitness within our study population. Furthermore, we suggest that small effects of isolation were due to the ability of Ortolan Buntings to move large distances within the breeding season, and that isolation effects on small spatial scales are more likely for species with restricted dispersal, such as resident species or species with high population density.

The importance of landscape heterogeneity and vegetation structure for the conservation of the Ortolan Bunting Emberiza hortulana

Summary Over the last decades, European farmland birds have strongly declined, mainly driven by agricultural intensification. The Ortolan Bunting Emberiza hortulana has suffered one of the most severe declines among farmland specialists. In order to maintain viable populations of the species in the long run, there is a vital need for evidence-based conservation measures. The main goal of this study was to detect the key drivers of breeding-territory selection and mating success of the species in an agricultural landscape in central Europe. We found that the landscape structure within the territories of Ortolan Bunting breeding pairs strongly varied from the overall habitat availability in the study area on both the territory and home-range scales. However, the environmental conditions also differed between the territories of breeding pairs and those of unpaired males. While landscape structure played an important role in breeding-territory selection, it had only weak effects on mating success. In contrast, crop type and vegetation height at potential nesting sites were important drivers of mating success. Overall, our study revealed that Ortolan Bunting has very complex breeding-habitat requirements. Only heterogeneous agricultural landscapes where (1) suitable song posts, (2) appropriate nesting sites, and (3) sufficient foraging habitats occur in close proximity are suitable for breeding. According to the findings of our study, agri-environmental schemes should primarily facilitate low-intensity farming practices that promote landscape heterogeneity, provide suitable nesting sites, and sustain a high abundance of invertebrate prey in farmlands.

Aridity, fire severity and proximity of populations affect the temporal responses of open-habitat birds to wildfires

The loss of open habitats in Europe has led to severe declines in birds associated with these habitats. However, certain ecological disturbances reverse the trend towards afforestation and create appropriate conditions for open-habitat species. Yet, open-habitat bird occupancy dynamics after disturbance depend on a complex combination of as-yet poorly studied factors. We analysed the colonization patterns and post-fire time-window of occurrence of open-habitat species along 687 transects in 68 burnt areas over a period of 11 years. During the study, 8345 individuals belonging to 22 open-habitat birds were detected. Species richness was related to an increased time elapsed since the fire, fire severity and proximity of potential population sources. Many species changed across the 11 years post-fire. Some species like the tawny pipit and the ortolan bunting, showed time lags affecting the timing of local extinction. Water deficit played a significant role in bird occurrence and six species benefited from drier conditions. Open-habitat species were more frequently detected in burnt areas near previously occupied areas and in severely burnt areas. Our results support the hypothesis that fire plays a critical role in the distribution dynamics of open-habitat species. Peak number of species was reached rapidly, between two and 6 years after fire, although a few species showed their peak abundance later on. An appropriate strategy for favouring open-habitat specialists in these landscapes, while reducing the risk of large wildfires, should prioritize integrated fire management to generate patches of different fire ages.

Spatial Heterogeneity of Steppe Bird Community in the Azov-Black Sea Enclave of the European Dry-Steppe Zone (Southern Ukraine)

Over the period 2007–2019, the author’s censuses of steppe birds in the Azov-Black Sea dry-steppe enclave determined five species as dominants and co-dominants by their abundance. Thus, Melanocorypha calandra dominates throughout the whole area, Emberiza calandra dominates in 4 subregions and co-dominates in 5 subregions, Motacilla feldegg, Emberiza hortulana, Anthus campestris, Alauda arvensis dominate in 1 subregion and do not dominate or co-dominate in 1–4 subregions. There is a general increasing trend in the total abundance of steppe birds and the number of their rare breeding species from north-west to south-east, whereas the number of their dominants and co-dominants grows in the opposite direction. According to the list, the correlation between the dominants/co-dominants and the number of rare breeding steppe species, it was revealed that the most valuable for the support of the steppe bird populations are subregions with the largest areas of virgin steppes (the Kerch Peninsula, Western and Central Crimea). The least important are the subregions with the highest degree of anthropogenic transformation (northern part of the Syvash region, western part of the Black Sea region) and the Lower Dnipro wetlands. Therefore, it is a high abundance of steppe birds and the maximum number of rare steppe species which should be a specific ornithological indicator of the status of zonal landscapes in the dry steppe zone (especially within protected natural areas of Ukraine) rather than general avian species diversity including introduced, invasive species, synanthropes, etc.

Habitat preferences of the Ortolan Bunting (Emberiza hortulana) in its prime wintering grounds, the cereal-dominated Ethiopian Highlands

Habitat preferences of the Ortolan Bunting (Emberiza hortulana) in its prime wintering grounds, the cereal-dominated Ethiopian Highlands

Habitat preferences of the Ortolan Bunting (Emberiza hortulana) in its prime wintering grounds, the cereal‐dominated Ethiopian Highlands

Agricultural intensification and land‐use changes are major factors impacting farmland biodiversity. The Ortolan BuntingEmberiza hortulanais the long‐distance trans‐Saharan migratory passerine that has undergone the most dramatic decline among all European farmland birds. The factors responsible for this decline may originate from the breeding grounds, migration stopovers and/or overwintering quarters. Very little is known about conditions on the species' wintering grounds, but a recent study has highlighted the utmost importance of the traditionally managed agroecosystems in the Ethiopian Highlands as a key wintering area, apparently harbouring as much as 90% of the world's Ortolan Bunting population. Using radiotracking and line transect surveys, this study aimed to provide fine‐grained information about species–habitat relationships in the Ortolan Bunting overwintering quarters. Our results showed the importance, at the landscape scale, of small‐scale agriculture, notably of traditionally managed, cereal‐dominated fields interspersed with semi‐natural structures. At a foraging‐site scale, on the other hand, patches of bare ground in combination with large areas of post‐harvesting stubble represented key habitat features. Stubbles provide an essential food resource and bare ground promotes ground foraging by enhancing food accessibility. The maintenance of a traditional agricultural economy will be essential to maintain the habitat potential for the Ortolan Buntings overwintering in the Ethiopian Highlands and will be instrumental in preserving its world population from further decline.

Is the Periodic "Spontaneous" Activity of Animals Determined by a Quasi-Rhythmic Factor of the External Environment?

We have studied the dynamics of the singing of garden bunting (Emberiza hortulana) and the dispersal of a flock of starlings (Sturnus vulgaris) for the night rest. The results were compared with the body temperature fluctuations measured in parallel in a group of laboratory mice. The validity of such comparisons was determined by the presence of a stable correlation between the indicators of minutely changes in body temperature in mice and greenfinches (Chloris chloris). The increase in the frequency of chanting of garden buntings was observed simultaneously with the increase in body temperature in mice. Moreover, the exact moments of the flights into the birdhouse for the night in starlings coincided with the maximums in the dynamics of minutely changes in body temperature of mice. These facts suggest an external synchronizer of "spontaneous" fluctuations of the activity and associated changes in body temperature, which are probably determined by the tone of the sympathetic nervous system.

Feather stable isotope (δ2H) measurements suggest no historical variation in latitudinal origin of migrants in two declining songbirds

The geographic origin of migratory birds can be traced using measurements of stable-hydrogen isotopes (δ2H) in their feathers. In continental Europe, local amount-weighted mean annual δ2H in precipitation varies with latitude, so that assignments of geographical origin of bird feathers are linked to latitude. Consequently, a potential northward latitudinal shift in the distribution of a species’ abundance is expected to translate into a shift in δ2H values for feathers grown on the breeding grounds. We analyzed δ2H in feathers from migrant individuals of Brambling (Fringilla montifringilla) and Ortolan Bunting (Emberiza hortulana) collected in France from the mid-nineteenth century to recent years (2015), to assess potential temporal trends in feather δ2H that may indicate changes in source populations or a shifting breeding range. These two species have shown long-term population declines in Europe with subsequent range retractions, but we did not find obvious differences in feather δ2H values in samples collected over the last 160 years. One potential explanation for this result is that population declines occurred similarly at all latitudes across the breeding ranges without involving a measurable latitudinal shift in abundance that could translate into changes in feather δ2H values. However, this result may also be due to potential temporally shifting terrestrial spatial δ2H gradients (i.e., isoscape) similar to a shift in bird abundances, or to limited northward range shifts that do not translate into detectable trends in feather δ2H.

Songbird presumed to be age‐limited learner may change repertoire size and composition throughout their life

AbstractSongbirds learn to sing by imitating their conspecific songs through social learning. It is commonly thought that in species with small repertoires, so‐called crystallization of the song repertoire takes place before the first breeding attempt and afterwards their repertoires remain unchanged. However, the number of studies in which individual song repertoires have been tracked longitudinally under natural conditions is still small. The ortolan bunting (Emberiza hortulana) is a small Eurasian passerine species. Studies on this species have shown that males have small song repertoires (usually 2–3), share the same final phrase within a local dialect area, and their repertoires remain unchanged during their lifetimes. We studied the whole, isolated Norwegian population of this species with 100–150 individually marked males. We compared repertoire sizes and contents using cross‐sectional and longitudinal approaches. We focused on marked males aged 2–10 years and recorded in up to five breeding seasons between 2001 and 2006. There was no local dialect because songs with different final phrases occurred both within and between males. Repertoire size varied between 1 and 24 (4.7 ± 3.4) song types per male. Longitudinal analysis showed an increase in repertoire size in 29% and a decrease in 21% of males. Males whose repertoires remained the same in size between years often substantially changed in contents. New song types appeared in almost 70% of males, and over 30% of males started singing new syllable types after the second calendar year. In almost 50% of males, new song types appeared that were built as new combinations of syllables shown in previous years. In 30% of males, the song complexity increased with age. Simultaneously, over 60% of males selectively ceased singing some song types. We suggest that these repertoire alterations are linked to the isolation and fragmentation of this population, which may affect song learning patterns through increased breeding dispersal and a strongly male‐biased sex ratio. Similar studies from abundant and continuous populations of the species are needed to test this idea.

Stable isotopes reveal captive vs wild origin of illegally captured songbirds in France

Naturally occurring stable isotopes of several elements are important tracers in the study the wildlife ecology including the identification of origins for migration research, investigations of trophic relationships, and in the forensic determination of illegally harvested and captive fauna. Extensive illegal trapping for use as decoys and in cuisine has contributed to drastic declines of Ortolan Bunting Emberiza hortulana populations breeding and migrating through France. We contrasted feather hydrogen isotope (δ2Hf) values in illegally captured and subsequently confiscated Ortolan Buntings (n=234), including feathers known to have grown in captivity (n=34) or of unknown growing environment (wild or cage), with δ2Hf values in birds legally caught (ringed and released) in the wild (n=40). We sought to determine if feathers from these bird groups could be differentiated based on this single isotope. Feathers grown in captivity had considerably lower δ2Hf relative to feathers of wild birds, which is potentially indicative of tap water consumption and the use of different diets in captive birds. Further, applying mixing models to δ2Hf values revealed similar proportions of captive vs. wild origins for birds illegally captured in 2012, 2014 and 2015, and a larger proportion of individuals with feathers grown in the wild in 2013. This potentially mirrors the confiscation of birds at poaching sites only in the former years, but also of recently caught wild buntings kept captive in 2013. Our results show that even a single stable isotope (δ2H) with good association with origins where feather keratins are produced is potentially useful in understanding origins of captive birds and may advance the monitoring of illegally captured birds.

Stable isotopes reveal the common winter moult of central rectrices in a long-distance migrant songbird

By analysing the deuterium concentration in the scapulars and rectrices (δ2Hf) of breeding and spring migrating Ortolan Buntings (Emberiza hortulana), we found a high correlation attesting that spring body and central rectrices have grown in similar isotopic environments. Furthermore, we failed to find a correlation between δ2Hf of the rectrices and the amount-weighted growing season precipitation δ2Hp of sites where we captured the birds. Winter-grown body coverts and rectrices displayed similar probabilistic assignments to origin. Further examination of 76 tails of breeding birds captured in Finland in May–June confirmed that breeding birds wear recently moulted central rectrices. The body coverts are known to moult during the winter partial moult in that species, but the rectrices have been reported to moult only once a year, during the complete post-breeding moult occurring on the breeding grounds in summer. Here, we reveal the common replacement of the central pair in winter, as well. The winter tail moult could occur beyond the central pair in some individuals, but this has still to be confirmed or refuted, by, e.g., further isotopic investigations.

Breeding prerequisites for Ortolan Bunting Emberiza hortulana in Swedish farmland with special focus on foraging

Ortolan Buntings Emberiza hortulana are rapidly decreasing in Sweden. Changes in agricultural practices are the main reason. Landscape simplification due to the removal of semi-natural elements leads to a lack of breeding habitats. Furthermore, due to intensive artificial fertiliser applications and advanced agricultural equipment and technology, crops grow both taller and denser than 50 years ago. In Kvismaren, south central Sweden, Ortolan Buntings have been studied since 2009. Here, we focus on one question: what defines a good foraging microhabitat? In 2017, nesting areas for five females and four males were identified and we did 271 feeding observations. Average foraging distance at different nests varied between 47 and 114 meters. About 70% of the foraging activities took place within crop fields. Ortolans utilized mainly unsown rows, later to be used by tractors for spraying etc. and patchy parts of standing crops. Invertebrates extracted from those areas looked dark, suggestive of ground-dwelling species. Our key management recommendation to create better microhabitats for feeding can be easily achieved by most farmers: to leave two unsown sowing rows (amounting to 0.38 m in width) for each tractor wheel to follow.

Unravelling migration connectivity reveals unsustainable hunting of the declining ortolan bunting.

In France, illegal hunting of the endangered ortolan bunting Emberiza hortulana has been defended for the sake of tradition and gastronomy. Hunters argued that ortolan buntings trapped in southwest France originate from large and stable populations across the whole of Europe. Yet, the European Commission referred France to the Court of Justice of the European Union (EU) in December 2016 for infringements to legislation (IP/16/4213). To better assess the impact of hunting in France, we combined Pan-European data from archival light loggers, stable isotopes, and genetics to determine the migration strategy of the species across continents. Ortolan buntings migrating through France come from northern and western populations, which are small, fragmented and declining. Population viability modeling further revealed that harvesting in southwest France is far from sustainable and increases extinction risk. These results provide the sufficient scientific evidence for justifying the ban on ortolan harvesting in France.

The use of soft songs during territorial intrusion in alarm context in the Ortolan Bunting Emberiza hortulana

Animals from many taxa produce low amplitude acoustic signals. In some birds such soft signals were found to be uttered in aggressive context and were the best predictor of subsequent physical attack. This phenomenon is poorly understood and several hypotheses have been proposed to explain the function(s) of the lowered amplitude of such signals. The eavesdropping avoidance hypothesis suggests that the use of low amplitude signals limits the possibility of signal detection by third-party receivers such as predators or conspecific rivals. Herein, we aim to investigate if soft songs in the Ortolan Bunting Emberiza hortulana are used in order to avoid being predated or eavesdropped by potentially threatening conspecifics. We simulated alarm situation by playback of conspecific alarm calls. We measured the overall strength of males’ response to territorial intrusion and number of soft songs in response to a risky situation compared to a control condition. Males showed a weaker approaching response to territorial intrusion and produced more soft songs if previously exposed to conspecific alarm calls and this behaviour is consistent with the eavesdropping avoidance hypothesis. However, we did not observe a complete switch to singing softly in alarm context, and both during the treatment and control males uttered loud calls in response. We suggest that soft songs in the Ortolan Bunting facilitate mediation of the territorial conflict by signalizing change in current motivation. Alternatively, soft songs might be related to readiness to fight or enable addressing signal to a specific receiver within a close range.

Sing softly to evoke a response only from a recent intruder

Low-amplitude soft songs have been described in many birds, but in most species, research has addressed only broadcast songs. Soft songs may have a similar or distinctive structure in comparison to broadcast songs produced in order to defend a territory and attract females. In some species, such soft songs were found to be produced in an aggressive context and were the best predictors of conflict escalation and later physical attack. However, such observations are not consistent across all species studied. Several hypotheses have been put forward to explain the function(s) of soft songs and why they are so quiet. Studies on the ortolan bunting (Emberiza hortulana) show that males produce soft songs similar in structure to broadcast songs during close interactions with conspecific intruders. However, experiments with the playback of loud and soft songs as well as taxidermic mount presentation revealed that soft song in this species does not fulfil aggressive signal criteria. Here we performed an experiment with two loudspeakers simulating movements of the intruder in order to test whether the soft songs are used to evoking a response from a nearby but not localised rival. We found that males responded with similar strength to songs played back from single and double speaker systems. Simultaneously, males produced more soft songs during and just after the phase of the experiment in which we simulated short flights of the intruder. Our results indicate that soft songs might be used during close interactions with rivals without being an aggressive signal and are used as short-range signals to check if the rival is still around. Our results also provide an alternative explanation of soft song behaviour in comparison to the hypotheses of eavesdropping avoidance and readiness to fight.

Den andra kända observationen av polygyni hos ortolansparv Emberiza hortulana

During field work on foraging of the Ortolan Bunting Emberiza hortulana in a small and isolated population at Kvismaren in the county of Örebro in south Sweden, two females, nesting 1,250 m apart were observed to be mate-guarded by the same colour-ringed male. Although the male commuted between the nests, none of the females seemed to obtain any substantial help from him when feeding the young. Polygyni has been reported only once before in this species, namely seventy-five years ago, also in a small population in Sweden, when a male behaved in a similar manner to that that we observed at Kvismaren.